OSAC Lexicon
The OSAC Lexicon is a compendium of forensic science terms and definitions. This terminology tool was created to help bring consistency and understanding to the way terms are used by the various forensic science. Use of the OSAC Lexicon does not replace the need to reference the original published source.
The terms and definitions in the OSAC Lexicon come from the published literature, including documentary standards and technical reports. It is continually updated with the latest work from OSAC units, as well as terms from newly published documentary standards and standards elevated to the OSAC Registry.
Gradually terms are evaluated and harmonized by the OSAC to a single term. This process results in an OSAC Preferred Term. An OSAC Preferred Term is a term, along with its definition, that has undergone review and evaluation by the FSSB Terminology Task Group and has been approved by the FSSB. The FSSB recommends that subcommittees use OSAC Preferred Terms when drafting standards.
The OSAC Lexicon should be the primary resource for terminology and used when drafting and editing forensic science standards and other OSAC work products.
Documentation that pertains to an investigation that can be requested and must be produced by the prosecution or the defense for trial purposes. For example, notes, records, certifications, photographs or digital media.
Documentation that pertains to an investigation that can be requested and must be produced by the prosecution or the defense for trial purposes. For example, notes, records, certifications, photographs or digital media.
The exchange of materials by the parties in relation to a legal proceeding.
The ability to recognize differences between two or more stimuli. Operational usage: The ability to recognize differences between two or more scents.
The ability to recognize differences between two or more stimuli. Operational usage: The ability to recognize differences between two or more odors/scents.
to distinguish between two samples based on meaningful differences; to differentiate
the ability of an analytical procedure to distinguish between two items of different origin
A stimulus that signals when a particular response produces specific consequences. For example, sitting in the presence of a particular odor/scent leads to a reward. The odor/scent in this case is the discriminative stimulus.
distinct features that occur in natural fibers (for example, flax, ramie, jute, hemp) in the shape of X's, ', and V's that are present along the fiber cell wall; these features are often useful for identification.
The variation of birefringence with wavelength of light.
Discussion—When dispersion of birefringence is significant in a particular fiber, anomalous interference colors not appearing in the regular color sequence of the Michel-Lévy chart can result. Strong dispersion of birefringence can also interfere with the accurate determination of retardation in highly birefringent fibers.
an optical staining technique in which colors are produced by the differential refraction of different wavelengths of light due to mounting the sample in a liquid having a different dispersion of refractive index.
Discussion—The procedure employs central or annular stops placed in the objective back focal plane of a microscope. Using an annular stop with the substage iris closed, a fiber mounted in a high dispersion medium shows a colored boundary of a wavelength where the fiber and the medium match in refractive index. Using a central stop, the fiber shows colors complementary to those seen with an annular stop.
the end of the hair farthest away from the root.
the end of the hair farthest away from the root.
The segment of a finger or thumb farthest from the palm.
A highly contagious viral disease of canids, including domestic canines, that is caused by a paramyxovirus genus Morbillivirus) and is marked by fever, leukopenia, and respiratory, gastrointestinal, and neurological symptoms, especially in young canines. In older canines symptomology may be less severe, but neurological impairment is always common.
a physical separation based on the vaporization of the different components of the mixture to be separated.
The tendency to be easily diverted from task.
Meaningful or meaning less blank-target sources that prevent concentration or diverts attention.
Non-target stimuli placed or naturally occurring within a search area. These can include: humans, toys, food, animal odor, etc.
Non-target stimuli placed or naturally occurring within a search area. These can include: humans, toys, food, animal odor, etc.
Non-target stimuli placed or naturally occurring within a search area. These can include: humans, toys, food, animal odor, etc.
Non-target stimuli placed or naturally occurring within a search area. These can include: humans, toys, food, animal odor, etc.
Non-target stimuli placed within a search area. These can include: humans, toys, food, animal odor, etc.
Non-target stimuli placed within a search area. These can include: humans, toys, food, animal odors or other blank-target odors/scents.
A change in the normal odor/scent picture of the area.
an abbreviation for maximum density. The abbreviation is used in describing both the characteristics of an image and/or an imaging device such as a scanner.
Deoxyribonucleic Acid. This is a chemical that forms a double helix that is unique to allbut identical siblings.
The process of identification and evaluation of biological evidence in criminal matters using DNA technologies, including DNA isolation and purification methods, data interpretation, statistical analysis, report writing, and courtroom testimony
DNA isolation and purification
A process by which the DNA concentration in a sample is determined.
A laboratory technique used to determine the sequence of bases (A, C, G, and T) in a DNA molecule.
An employee who is accountable for the technical operations of the laboratory and who is authorized to stop or suspend laboratory operations.1
Abbreviation for deoxynucleotide tri-phosphates; used in PCR as building blocks to construct new DNA strands.
Any material that conveys a message or contains information on which a set of observations can be made. May be used interchangeably with “item”.
The trained person who works the canine. (See canine handler.)
This term has two uses in this standard: Implementation domain refers to the group of organizations or agenciesthat have agreed to use a specified set of user-defined fields in a particularformat. This is the domain encoded in Field 1.013: Domain name /DOM. NIEM biometrics domain refers to an XML namespace that conforms withthe NIEM naming rules. It deals with biometric data. See Annex C:NIEM-conformant encoding rules for details.
smokeless powder that contains both nitrocellulose and nitroglycerin.
propellant containing nitrocellulose and nitroglycerin.
Scientific usage: This condition occurs when neither the experimenter/canine handler, nor the observer/evaluator, knows which treatments/manipulations are given to which subjects. Operational usage: In the evaluation of a canine team, neither the assessor nor the canine handler knows the location of the target odor/scent or whether target odor/scent is present (i.e., a blank/null search).
In the evaluation of a canine team neither the assessor nor the canine handler knows the location of the target odor/scent or whether target odor/scent is present (i.e., a blank / null search).
Scientific usage: This condition occurs when neither the experimenter/canine handler, nor the observer/evaluator, knows which treatments/manipulations are given to which subjects. Operational usage: In the evaluation of a canine neither the assessor nor the canine handler knows the location of the target odor/scent or whether target odor/scent is present (i.e., a blank/null search).
In the evaluation of a canine neither the assessor nor the canine handler knows the location of the target scent or whether target scent is present (i.e., a blank/null search).
In the evaluation of a canine neither the assessor nor the canine handler knows the location of the target scent or whether target scent is present (i.e., a blank/null search).
In the evaluation of a canine neither the assessor nor the canine handler knows the location of the target scent or whether target scent is present (i.e., a blank/null search).
(1) in audio, image, and video analysis, to retrieve audio, video, image, or transactional data from a recording device (for example, DVR system); (2) in computer forensics, to receive data from another digital source.
Bone that no longer retains its visco-elastic properties (it could still be associated with tissue, but that tissue would likely be mummified).
A method utilizing the layering of dry dental stone powder and misted water.