Forensic Science Glossary

AAFS – American Academy of Forensic Sciences.

Abrasion – An injury to the skin that removes the epithelial layer.

Accelerant – A flammable substance used to create and spread fire.

Accident Reconstruction – Using physical evidence a re-create a crime or accident scene.

Acid Phosphate Test – A test to reveal the presence of seminal fluid, appearing purple when positive.

Adipocere – A waxy, soap-like substance that forms on corpses during decomposition under specific conditions. Also known as ‘grave wax’.

AFIS – Automated Fingerprint Identification System.

Aggravating Circumstances – Conditions which make a crime more serious.

Agglutination – The tendency of blood cells to clump together in reaction to an antibody.

Algor Mortis – The reduction in body temperature after death.

Allele – Any of multiple forms of a gene located at the same point on a particular pair of chromosomes.

ALS (Alternative Light Source) – Any alternative source of light generally used for enhancing latent prints, biological fluid, and trace materials.

Antemortem – Prior to death.

Anthropology – The science of the origin, culture, and development of human beings. In forensics, this mainly involves the analysis and identification of skeletal remains.

Anthropometry – Devised by Alphonse Bertillon, a method of using a person’s key body measurements as a means of identification.

Apnoea – See ‘asphyxia’.

Arches – A characteristic pattern of fingerprint ridges, possessed by approximately 5% of the population.

Arson – Intentionally causing a fire to destroy the property in a criminal manner.

Asphyxia – Death caused by suffocation as a result of the lack of oxygen and increase of carbon dioxide in the blood. Also known as apnoea.

Atomic Absorption Spectroscopy – A method of analysing gunshot residue.

Autoerotic Accident – A death usually occurring from asphyxia produced by masturbatory rituals.

Autopsy – The internal medical examination of a body used to determine the cause and circumstances of death.

Autoradiograph – Also known as an autorad, this is the final product in DNA analysis, having a similar appearance as a barcode.

Ballistics – The science of projectiles, particularly bullets.

Barefoot Morphology – The science of reading footprints in order to establish the pace, size, and body weight of the individual.

Bertillonage – Invented by Alphonse Bertillon, a now obsolete method of classifying human beings by a set of body measurements.

Blood Analysis – See ‘serology’.

Blood Group – One of the four ways to categorise a person based on the antibodies and antigens in their red blood cells; A, B, AB, and O.

Blood Pooling – The congestion of blood in the lowest areas of a dead body. See ‘hypostasis’.

Blood Spatter – The impact of blood on surfaces.

Blood Spatter Pattern Analysis – The examination of blood spatter patterns to determine the events which took place before, during and after the spilling of the blood.

Bloodstain Interpretation – The interpretation of the shape, size, orientation, and distribution of bloodstains.

Botany – The scientific study if plants, relevant to forensics in terms of plant matter found at a crime scene or on an item of evidence.

Brainprint – Technology used to determine whether a brain registers a memory, particularly a criminal act.

Buccal Swab – A swab taken from the mouth to collect epithelial cells for DNA analysis.

Bullet Track – The path a projectile takes as it passes through matter.

Bullet Wipe – A dark, ring-like mark found around an entrance wound, composed of lead, carbon oil and dirt.

Cadaveric Spasm – The sudden rigidity of the muscles immediately after death.

Calibre – The internal diameter of the gun barrel or bullet, expressed in hundredths of an inch.

Capital Punishment – The death sentence.

Cartridge Case – A small cylinder of metal or pasteboard which holds a charge of powder and often a bullet.

Case Linkage – The discover of links between cases which were previously thought to be unrelated.

Cast-off Stains – Blood spatter produced when a bloodied object is pulled back from a blow.

Cause of Death – An injury or disease that ultimately leads to death of the individual, generally determined by medical examiners or coroners.

Chain of Custody – A method of keeping track of who has handled a piece of evidence, when, and for what purpose. Vital in ensuring evidence is not damaged or altered in any way.

Character Disorder – A personality disorder manifested in patterns of behaviour.

Choke – The constriction of a shotgun barrel to reduce the spread of the shot, thus increasing its range.

Chromatography – A technique used to separate a sample into its components based on the speed at which they move through a stationary matrix.

Chromosome – A component found inside most human cells consisting of long coils of DNA. Humans have 23 pairs of chromosomes, one set inherited from each parent.

Circumstantial Evidence – Evidence from which a logical conclusion of a fact may be drawn.

Clavicle – The collarbone linking the scapula and sternum.

CODIS – The Combined DNA Index System, the FBI database of genetic information.

Cold Case – An unsolved case which is still open but no longer being actively investigated.

Comparison Microscope – Two compound microscopes combined into a single unit, allowing objects to be placed under each and viewed side by side through a single eyepiece.

Composite Drawing – A sketch composed of a suspect produced from one or more eyewitness description.

Compound Microscope – A basic microscope composed of two lenses which focus a magnified image of the subject on the retina of the observer’s eye.

Computer Forensics – The application of computer technology and techniques to aid legal investigations.

Concentric Fractures – Patterns of cracks in glass pierced by a projectile such as a bullet which runs between the radial fractures.

Contact Wound – A wound occurring when the firearm is fired whilst placed against a surface.

Contusion – A soft haemorrhage from a blunt trauma.

Coroner – A medical examiner or elected official who may, in some jurisdictions, lead a death investigation.

Corpus Delicti – The essential body of facts that suggest a crime has occurred. From the Latin ‘body of crime’.

Cortex – The central portion of a hair containing the pigment which gives hair its colour.

Crime Scene Reconstruction – The use of evidence to determine the events which occurred at a crime scene.

Crime Scene Staging – The alteration of a crime scene in order to reduce its evidentiary value.

Criminalistics – The field of science applying science to law and criminal investigations.

Criminal Profiling – The analysis of the crime scene and crime patterns to assign relevant characteristics to a perpetrator in order to aid law enforcement in narrowing the field of suspects.

Criminology – The study of criminal activity and legal procedure.

Cuticle – The protective outer sheath of a hair, composed of a series of overlapping scales.

Cyanide – A highly poisonous water-soluble chemical composed of carbon and nitrogen.

Dactyloscopy – The development and identification of fingerprints.

Decomposition – The disintegration of body tissues after death.

Delta – A characteristic junction in a loop ridge fingerprint pattern.

Density Gradient Tube – Equipment used for measuring the distribution of different particles in a soil sample by establishing the point at which they are suspended in a tube filled with layers of liquid of different densities.

Density Test – A test in which glass fragments are floated to establish if they are from the same source.

Dental Stone – A casting material commonly used for making impressions of footprints and tires.

Diatom – Microscopic algae found in bodies of water, beneficial in narrowing down the source of a water sample.

Diminished Capacity – A psychological defence indicating the inability of an individual to understand the nature of a crime or to control their actions.

Disarticulation – The separation of bone joints.

DNA – Deoxyribonucleic acid. The genetic material contained in cells.

DNA Profile – A composite of genetic markers uniquely characterising an individual.

DNA Profiling – Creating a DNA fingerprint from a biological sample for use in comparison and the identification of an individual.

Dry Drowning – Death caused by asphyxiation resulting from muscular paralysis brought on from the shock of the victim falling into the water.

Electroencephalograph – A device used to measure the electrical activity of the brain, converting the information into a readable report.

Electron Microscope – A microscope which uses a beam of electrons to focus a specimen.

Electrophoresis – A technique used to separate DNA fragments. The DNA is placed in a charged gel, the charge causing the fragments to move towards one pole at different rates.

Entomology (forensic) – The scientific study of insect evidence to aid a legal investigation.

Equivocal Evidence – Evidence that supports more than one theory.

Evidence – Any items, documents and statements that are included in a legal investigation for the jury’s or judge’s consideration in the determination of an individual’s guilt or innocence.

Expert Witness – An individual with a specialised knowledge of a certain field that can assist in the understanding of complicated information or offer an expert opinion.

Femur – The thighbone, the longest bone in the body. In anthropology, this may be measured and used as a guide to the height of the individual.

Fibre – A thin, threadlike material, often from some kind of fabric.

Fingerprint – The unique pattern created by the ridges found on the palm side skin of fingers and thumbs.

Firing Pin – A device in a gun which strikes the primer, igniting the projectile’s propelling charge.

Floater – A corpse found in water, often floating due to the built up on gas in the abdomen resulting from decomposition.

Forensic Science – The application of all forms of science to aid legal investigations.

Forgery – An attempt to replicate the original item and pass it off as authentic.

Formaldehyde – A pungent gas used as a disinfectant, antiseptic, and fixative for tissues.

Gas Chromatography – A method of breaking down a compound into its individual components as they travel through a non-reactive gas.

Gel Electrophoresis – A method used to divide a DNA sample into its components through the application of an electric charge.

Gene – The segment of DNA that codes for the production of a particular protein.

Geographic Profiling – The utilisation of the geographic relationship between crime scenes to conclude any similarities or other points of interest.

Graphology – The art of determining individual characteristic traits of a person based on his or her handwriting.

Grid Search – A crime scene searching pattern. The scene is segmented into smaller areas, each of which is individually searched for evidence.

Gun Shot Residue – Also known as GSR. The unburned powder propelled from a gun when a bullet is fired. It will often be found on the clothing or skin of the shooter or victim.

Hemastix – A presumptive blood testing tool.

Haemoglobin – The protein in a red blood cell responsible for carrying the oxygen in the bloodstream.

Haemorrhage – A severe bleed.

High-Risk Victim – An individual who is continuously exposed to danger, such as drug users and prostitutes.

HITS – Homicide Investigation racking System, Washington State’s database used to link violent crimes through signature analysis.

HOLMES – The Home Office Large/Major Enquiry System, the UK’s main police computer system.

Homicide – Murder, a death caused by another person.

Hyoid – A u-shaped bone at the base of the tongue which supports the tongue muscles.

Hypostasis – Also known as lividity. The pooling of blood at the lowest parts of the body. Usually commences between six and eight hours after death has occurred.

Hypoxia – Decrease in oxygen to the brain.

Immunoassay – A test which utilises antibodies to identify and quantify substances.

Impression Evidence – The evidence left by anything that leaves a kind of impression at the scene or on an item, such as footprints, tire tracks, or toolmarks.

Indent – An impression left on paper caused by the force from a pen tip.

Infrared – A band of the electromagnetic spectrum which cannot be seen by the human eye.

Infrared Spectroscopy – A type of spectroscopy using infrared light.

Inorganic Compound – A substance that is not carbon-based.

Insanity – The legal term for a mental disease or defect that may essentially absolve the person of responsibility.

Iodine Fuming – A form of developing latent fingerprints using the fumes of iodine.

Ion Detector – A device that detects the presence of accelerants in the air.

IP Address – The specific numeric address of a computer.

Jurisdiction – The authority to exert power legally within a specific area.

Kastle-Meyer Test – A presumptive blood test.

K9 – A specialised evidence response team utilising specially trained dogs to train certain scents, such as drugs, accelerants, and individuals.

Laceration – The splitting or tearing of the skin.

Larvae – The young of an insect prior to metamorphosis.

LASER – Light Amplification by Stimulated Emission of Radiation. A device used to produce a beam of optical radiation by stimulation of electronic, ionic, or molecular transitions to create energy.

Latent Fingerprint – A fingerprint left by deposits of the skin’s oils, usually requiring some form of treatment in order to visualise it.

Lie Detector – See “polygraph”.

Ligature – An object used to bind or strangle someone.

Livescan – Technology allowing the fingertips to be scanned rather than rolled in ink to obtain a fingerprint.

Lividity – See “hypostasis”.

Livor Mortis – See “hypostasis”.

Locard’s Exchange Principle – Every contact leaves a trace. A theory stating that anyone who enters a crime scene will leave something behind or take something away.

Locus – A specific site on the chromosome.

Low Copy Number – LCN. A new technique used to obtain a DNA profile from a fingerprint or small amount of tissue.

Luminol – A chemical reagent used to visualise latent blood stains.

Manner of Death – The way in which death was caused; homicide, suicide, accidental, natural, or undetermined.

Mass Killer – An individual who kills many people at the same time.

Mass Spectrometry – A method of identifying the components of a compound by bombarding the sample with electrons. Medical Examiner – In some locations, the individual who runs a death investigation or performs autopsies.

Microspectrophotometry – A method of identifying a sample by emitting a beam of electrons over the specimen and analysing the election emissions created.

Mitigating Circumstances – Factors that may diminish the degree of guilt in a criminal offence, such as age or influence of drugs.

Mitochondrial DNA – A form of DNA found in the mitochondria, indicating maternal heritage only.

MO – Method of operation, from the Latin Modus Operandi. The method by which a crime is committed.

Multiple Personality Disorder – Also known as dissociative identity disorder. A psychological condition in which the individual appears to have two or more distinct personas.

Mummification – The desiccation of a body due to very hot and dry conditions, or exposure to very cold temperatures.

NCAVC – National Centre for the Analysis of Violent Crime. A subdivision of the FBI’s Behavioural Science Unit.

NDNAD – National DNA Database, the UK’s database of DNA profiles.

Neutron Activation Analysis – A technique used on trace evidence by bombarding the sample with neutrons in a nuclear reactor.

Nucleus – The section of the cell containing the DNA and RNA.

Odontogram – A file containing an individual’s dental information.

Odontologist – An individual specialising in dentistry, particularly bite mark impressions.

Odontology – The study of the teeth, including their anatomy, growth and diseases.

Orthotolidine – A solution used to determine whether a stain contains blood.

Ossification – The process by which bone is formed. A mesh of collagen fibres is formed, after which a polysaccharide is produced. Finally, small calcium salt crystals are placed in this polysaccharide to form the bone.

Ouchterlony Test – A test used to determine whether a blood stain is of animal or human origin.

Palynology – The study of pollens.

Pathology – A branch of medical science studying the cause, nature and effect of diseases.

Pattern Evidence – Evidence which can be read from a specific pattern, such as a show impression.

Perimortem – The period of time immediately before death.

Petechial Haemorrhage – A minute, pin-like haemorrhage that occurs beneath the skin.

pH – The measure of acidity or alkalinity of a substance.

Phenolphthalein – A substance used alongside hydrogen peroxide which produces a deep pink colour in the presence of blood.

Phrenology – A now discredited theory that believes the shape of an individual’s head can indicate their personality.

Physical Evidence – Any object relevant to the occurrence of a crime.

Plasma – The standard constituent of blood in which the various blood cells are carried.

Polygraph – A machine used to monitor bodily functions which may change when an individual lies.Not admissible in court.

Polymer – A long-chain molecule composed of many repeated units.

Polymerase Chain Reaction – PCR. A technique that replicates a section of a DNA strand, allowing millions of copies to be produces from a minute sample.

Portrait Parle – A 19th century system for regularising verbal descriptions of a suspect’s facial features.

Postmortem – After death.

Postmortem Interval – PMI. The time since death.

Precipitin Test – A test used to determine whether a blood sample is of animal or human origin, done so by the treatment of human anti-serum.

Primary Flaccidity – The general relaxation of the entire muscular system after death. This will usually only last between two to eight hours.

Probe – A fragment of DNA which carried the complementary code for a base sequence.

Prostate Specific Antigen – PSA. A substance in human seminal fluid used to confirm the presence of human semen.

Psychological Profile – A method of gathering speculative information regarding a suspect’s psychological makeup in order to aid the investigation.

Psychological Stress Evaluator – A device used to measure stress levels in a recorded voice.

Psychopathy – A personality disorder defined by specific antisocial behaviour and often including a lack of guilt or remorse.

Puncture Wound – An injury caused by the piercing of the body, often by a hand-held object.

Putrefaction – One of the final changes to take place in the human body, essentially the anaerobic bacterial digestion of the remains.

Questioned Documents – Any item containing writing that requires analysis to confirm the likes of authorship or authentication.

Radial – A pattern formation in a fingerprint in which a loop forms and opens towards the thumb.

Radial Fractures – Star-shaped fractures formed when a sheet of glass is pierced by a bullet, originating on the opposite side to the initial impact.

Radius – The outer and shorter of the two human forearm bones.

Rape Kit – A collection of items used to process a rape victim for items of evidence that may indicate the perpetrator.

Refractive Index – The measure of degree through which light passes through a particular substance.

Restriction Fragment Length Polymorphism (RFLP) - The original method for obtaining a DNA profile, in which the molecule is cut into pieces and the different lengths analysed.

Rhesus Factor – The presence of absence of a particular antibody, allowing for further differentiation between blood of different individuals.

Ridge Characteristics – The endings, bifurcations, enclosures and similar ridge details in a fingerprint.

Rifling – The lands and grooves cut into the barrels of a gun.

Rigor Mortis – The stiffening of the body after death due to a chemical reaction occurring in the muscles. Usually appears between two and eight hours after death, lasting between sixteen and twenty-four hours.

Saponification – A process which may occur during putrefaction in which parts of the body are converted into adipocere (see “adipocere”).

Scanning Electron Microscope – A device which uses beams of electrons to form the image of a specimen.

Scent Pad – Used to store a scent for use with trailing dogs.

Sciatic Notch – The characteristic shape of the part of the hipbone which may indicate the sex of a skeleton.

Secondary Flaccidity – The secondary relaxation of the body’s muscles following death.

Seminal – Pertaining to semen.

Serrated – Saw-like. Having a row of sharp, tooth-like projections.

Serial Crime – Any type of crime occurring in a pattern indicating a single offender.

Serial Killer – An individual who has murdered three or more people with a cooling-off period in between.

Serology – The analysis of bodily fluids such as blood, saliva and semen.

Short Tandem Repeats (STR) – A method used to obtain a DNA profile after replication through PCR has occurred. STRs are short sequences in the DNA molecule that repeat themselves at numerous points in the genome.

Signature Crime – A crime scene bearing the individual ‘stamp’ of a particular offender.

Slippage – The sloughing off of the flesh on a cadaver.

Spalling – The cracking of concrete in a fire, indicating how hot it burned.

Spectrometry – The detection of wavelengths of light.

Speculative Search – A search based on information rather than actual evidence.

Spree Killer – An individual who murders numerous people with no cooling-off period in between.

Stippling – Minute burn marks left by gunpowder as it leaves the gun, also known as tattooing.

Strangulation – The prevention of respiration by the compression of the air passage.

Striations – Fine markings left behind on an item, such as on a bullet, caused by rifling in the barrel.

Super Glue Fuming – A method of developing latent fingerprints using the fumes of cyanoacrylate or a similar substance, which adheres to the oils in the fingerprint, visualising it.

Swap File – A file used to temporarily store information when a system’s memory is low.

Tape Lift – An adhesive used to lift trace evidence from a crime scene or object.

Tattooing – See “stippling”.

Thin-Layer Chromatography – A technique used for separating a sample into its components based on the speed at which they move up a plate coated thinly with silica gel.

Tibia – The shin bone, commonly used to calculate the height of an individual’s skeletal remains.

Tomography – Obtaining an X-ray image of a selected layer in an object.

Toxicology – The study of drugs, poisons and their effects on the body.

Trace Evidence – Minute pieces of evidence found at the crime scene, including fibre, hair, glass, seed, and soil.

Trajectory – The path of a fired projectile.

Trauma – A physical injury caused by external violence.

Ulnar – A loop pattern in a fingerprint which opens towards the little finger.

Ultra Violet – UV light, used to fluoresce various substances, including urine, saliva and semen.

Vertebrae – One of the twenty-four segments of the human spinal column.

ViCAP – Violent Criminal Apprehension Program, the FBI’s nationwide data information centre.

Victimology – The study of victim information in order to obtain details of a perpetrator’s opportunity and selection process.

Visceral Temperature – The Temperature of the internal organs, particularly those within the abdomen and thorax.

Vitreous Humor – The fluid filling the eyeball. This changes after death, potentially being useful in determination of the post-mortem interval.

Voiceprint – A graph electronically composed of the amplitude and vibrations of the human voice.

Whorls – A pattern within a fingerprint in which the ridge makes at least one complete circuit.

Wick Effect – The effect of an individual’s body fat feeds a smouldering flame, burning the person to ash without surrounding items being burned.

Wisdom Teeth – The third molar teeth, usually erupting in the late teens to early twenties.

Y Incision – An incision made during an autopsy, a cut from shoulder to shoulder, meeting at the sternum, and down to the groin. This exposes the internal organs for examination.

Zoology – The study of animals, their life and behaviour.


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