Forensic Science Glossary

• These are study notes for a glossary of forensic science terms
• Include all key facts, figures, and entities
• Omit meta information, personal information, and references not directly related to the topic
• Focus on actual subject matter, avoid stating "the definition is", just state the facts directly

Abrasion

• A mark from pressure when a surface slides across another.

Accumulated Degree Hours (ADH)

• The hours at an adjusted average temperature needed for an insect species to develop to a specific stage.

Addiction

• A physical process where a person craves a drug.
• Failure to take the drug can cause withdrawal symptoms.

Agglutination

• Clumping of cells caused by an antigen.

Algor Mortis

• The cooling of the body after death.

Allele

• An alternative form of a gene.

Amorphous

• Without a defined shape or form.
• Describes fibers with a loose arrangement of polymers that are soft, elastic, and absorbent (e.g., cotton).
• Describes solids with atoms arranged randomly instead of in a pattern.

Analytical Skills

• The ability to:
  • Identify a concept or problem.
  • Isolate its component parts.
  • Organize information for decision making.
  • Establish criteria for evaluation.
  • Draw appropriate conclusions.

Angiosperm

• A flowering plant that produces seeds within a fruit.

Angle of Impact

• The angle at which blood strikes a target surface relative to its horizontal plane.

Antibodies

• Proteins secreted by white blood cells that attach to specific antigens.

Antigen

• A substance that provokes an immune response in the body.

Antigen-Antibody Response

• Antibodies attach to specific antigens
• This causes agglutination in cross blood-type transfusions.

Arch

• A fingerprint pattern where the ridge pattern originates from one side and continues to the other.

Area of Convergence

• A two-dimensional view of the intersection of lines drawn through the main axis of at least two blood drops.
• Indicates the general area of the blood spatter's source.

Area of Origin

• The location of the blood source in three dimensions.
• Determined by projecting angles of impact of individual bloodstains.

Assemblage

• A group of plant species in an area, dominated by one species, sharing habitat requirements.

Autolysis

• The breakdown of cells as they self-digest.

Autopsy

• A medical examination to determine the cause of death.

Backscatter

• Fragments of glass left on the side of an impact.

Ballistics

• The study of a projectile in flight.
• Includes the launch and behavior of the projectile.

Biological Profile

• Estimation of the deceased's sex, age, stature, and ancestry.
• Includes diseases and injuries derived from skeletal remains analysis.

Breech

• The end of the barrel attached to the firing mechanism of a firearm.
• The location where the cartridge is loaded and unloaded.

Bullet

• The projectile fired when a firearm is discharged.

Bullet-Resistant ("Bulletproof") Glass

• Laminated and tempered glass composed of two layers.

Caliber

• The inside diameter of a firearm barrel.

Cartridge

• A case that holds a bullet, primer powder, and gunpowder.

Cast-Off Pattern

• Blood projected onto a surface from an object in motion.

Cause of Death

• The injury or condition responsible for a person's death.
• Examples: heart attack, kidney failure.

Chain of Custody

• The documented and unbroken transfer of evidence.

Chromosome

• A nuclear cell structure that contains DNA in humans.

Circumstantial Evidence

• (Indirect evidence)
• Evidence used to imply a fact but not support it directly.

Class Evidence

• Material that connects an individual or thing to a certain group.

Clay

• The finest soil particles that can absorb and hold water.

Combined DNA Index System (CODIS)

• The FBI's computerized criminal DNA databases and software.
• Includes the National DNA Index System (NDIS).

Comparison Microscope

• A compound microscope that allows side-by-side comparison of samples, like hair or fibers.

Complete Metamorphosis

• Body development in four stages: egg, larva, pupa, and adult.

Concentric Fracture

• A circular pattern of cracks that forms around a point of impact.

Controlled Substance

• A drug or chemical compound regulated by the legal system regarding manufacture, distribution, possession, and use.

Controlled Substances Act

• Law that established penalties for illegal drug possession, use, or distribution.
• Established five schedules for classifying drugs.

Core

• The center of a loop.

Coroner

• An elected official who certifies deaths.
• May be a layman or physician.
• Authority to order investigations of suspicious deaths.

Cortex

• The region of a hair located outside the medulla that contains granules of pigment.

Counterfeiting

• Forging currency.
• Also forging government-issued documents and producing fake name-brand products for profit.

Crime-Scene Investigation

• A multidisciplinary approach where scientific and legal professionals work together to solve a crime.

Crime-Scene Reconstruction

• A hypothesis of the sequence of events from before the crime through its commission.

Crop

• A digestive organ used for storage of food.

Crystalline

• Geometrically shaped.
• Fibers composed of polymers packed side by side, making them stiff and strong (e.g., flax).

Currency

• A printed document issued by a bank, guaranteeing payment to the holder on demand.

Cuticle

• The tough outer covering of a hair composed of overlapping scales.

Cutting Mark

• A mark produced along the edge of a surface as it is cut.

Datum Point

• A permanent, fixed point of reference used in mapping a crime scene.

Decomposition

• The breakdown of once-living matter by living organisms.

Deductive Reasoning

• Deriving a conclusion from facts using logical steps.

Delta

• A triangular ridge pattern.

Density

• The ratio of mass to volume; density = mass/volume.

Dependency

• Powerful craving for a drug.
• Does not result in physical withdrawal upon discontinuation, unlike addiction.

Depressant

• A substance that decreases or inhibits the nervous system, reducing alertness.

Diaphysis

• The shaft of a bone.

Direct Evidence

• Evidence that supports an alleged fact of a case, if authentic.

Direct Transfer

• The passing of evidence, such as a fiber, from victim to suspect or vice versa.

DNA Fingerprint (Profile)

• Pattern of DNA fragments obtained by analyzing a person's unique noncoding DNA sequences.

Document Analysis

• Examination of questioned documents with known material.
• Uses criteria such as authenticity, alterations, erasures, and obliterations.

Document Expert

• A person who scientifically analyzes handwritten, typewritten, photocopied, and computer-generated documents.
• Analyzes documents, and their materials, for authenticity

Electrophoresis

• A method of separating molecules, such as DNA, according to size.

Entomology

• The study of insects and related arthropods.

Epiphysis

• The unattached end of a bone that eventually fuses with the bone shaft.

Exemplar

• A standard document of known origin and authorship.
• Used in handwriting analysis for comparison to questioned documents.

Exon

• The portion of a gene that is expressed.

Eyewitness

• A person who observed something related to a crime and can communicate their observations.

Fact

• A statement or information that can be verified.

Fiber

• The smallest indivisible unit of a textile.
• Must be at least 100 times longer than wide.

Fingerprint

• An impression left on any surface.
• Consists of patterns made by ridges on a finger.

Firearm

• A portable gun that uses a confined propellant to expel a projectile out of a barrel.

First Responder

• The first safety official to arrive at a crime scene.

Forensic

• Relating to the application of scientific knowledge to legal questions.

Forensic Anthropology

• The use of skeletal anatomy to identify remains for legal purposes.

Forensic Botany

• The application of plant science to crime-scene analysis for use in the resolution of legal cases.

Forensic Entomology

• The application of entomology to civil and criminal legal cases.

Forensic Palynology

• The use of pollen and spore evidence to help solve criminal cases.

Forgery

• Making, altering, or falsifying personal documents or other objects with the intention of deception.

Fraudulence (Fraud)

• Deliberate deception to secure unfair or illegal financial gain.

Gas Chromatography

• A method of separating chemicals to establish their quantities.

Gene

• Segment of DNA that codes for a trait.

Genome

• All the DNA found in human cells.

Geology

• The study of soil and rocks.

Glass

• A hard, transparent, amorphous, brittle solid made by heating a mixture of silica and other materials.

Groove (of a Tire)

• A depression in the tread.

Growth Plate (Epiphyseal Plate)

• Area of cartilage between the shaft and cap of an immature bone.
• Responsible for the lengthening of bone.

Grub

• Wormlike beetle larva.

Gunshot Residue (GSR)

• Soot and unburned gunpowder particles deposited on a person who discharges a firearm.
• May be found on close-range victims and adjacent surfaces.

Gymnosperm

• Plants with "naked" seeds not enclosed in a protective organ (fruit); most are evergreens.

Hair Follicle

• The actively growing base of a hair that contains DNA and living cells.

Hair Shaft

• Part of the hair above the follicle.
• Contains mitochondrial DNA.

Hallucinogen

• A drug that changes a person's perceptions and thinking during intoxication.

Humus

• Material in the uppermost layer of soil.
• It is made up of the decaying remains of plants and animals.

IAFIS (Integrated Automated Fingerprint Identification System)

• FBI-developed national database of over 76 million criminal fingerprints and histories.

Illegal Drug

• A drug that causes addiction, habituation, or a marked change in consciousness.
• Has limited or no medical use.
• Listed in Schedule I of the U.S. Controlled Substances Act.

Indentation Mark

• A mark or impression made by a tool pressed directly onto a softer surface.

Individual Evidence

• A kind of evidence that identifies a particular person or thing.

Study notes defining key forensic science terms. Includes abrasion, accumulated degree hours(ADH), addiction, agglutination, algor mortis, allele, amorphous, etc. Terms cover forensic science, biology, and entomology.