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.
A mutation that results in a change from a purine to pyrimidine or vice versa (e.g., A-to-T).
The designed part of the tire that comes into contact with the road.
A single geometric component of a tire tread design.
A vertical measurement between the top of the tread to the bottom of the tire's deepest groove, measured in 32nds of an inch.
A device used to measure the depth of the tire tread.
A specific pattern or arrangement of design elements on a tire tread typically associated with a manufacturer and having a name and/or style number. (Also used to describe footwear outsoles.)
A term used to describe a specific pattern or arrangement of design elements on a tire treadtypically associated with a manufacturer and having a name and/or style number (also used todescribe footwear outsoles).
Bands of raised rubber, sometimes called 'wear bars', that are 2/32 of an inch above the bottom of the main grooves of a tire.
Bands of raised rubber, sometimes called wear bars, that are 2/32 of an inch above the bottom of the main grooves of a tire.
The width of the tire tread from one edge to the other in an impression. Not to be confused with section width.
A commercial product used to make inkless tire test impressions. POUBLISHER NOTE: This term is used as an example only, and does not constitute an endorsement of this product by the AAFS Standards Board
The sensor in a flatbed scanner, or digital scanning back, which is made up of three rows of pixels with a red filter covering one row, a green filter covering the second row and a blue filter covering the third row.
A condition characterized by apparent or actual knotting of the hair.
A condition characterized by longitudinal splitting or fraying of the hair shaft.
A genetic disease characterized by a segment of bulbous, dilated hair enfolded into a concave hair terminal, recalling the appearance of a bamboo node; if the hair breaks at the bulbous end, the hair has a 'golf-tee' shaped end.
A condition characterized by the formation of nodes; the hair is weaker at the node and subject to breakage.
A condition in which the hair readily breaks or splits along transverse cracks.
The amount of force which must be applied to the trigger of a firearm to cause sear release. The direction of the applied force is approximately parallel to the bore axis.b
The amount of force which must be applied to the trigger of a firearm to cause sear release.
an ester of three fatty acids and glycerol.
Propellant containing nitrocellulose, nitroglycerin, and nitroguanidine
A conversation is a sequence of conversational turns. A turn is when an individualspeaks for a continuous period of time. Individual turns from different people mayoverlap when they speak simultaneously. However, typically a turn is referred to in aquestion / response environment.
The diameter of the smallest circle produced during a vehicle's tightest turn, as measured from the outer edge of the outmost front tire in that turn.
the number of turns about the axis applied to a fiber, yarn, strand or rope over a given length to combine the individual elements into a larger and stronger structure.
The number of turns about the axis applied to a fiber, yarn, strand or rope over a given length to combine the individual elements into a larger and stronger structure
An impression with dimensions of length and width.
This is the mistake when one rejects the null hypothesis (one states that there is an effect) and it is true (there is really NO effect). This is also called a false positivedetecting an effect where none exist. (see false positive.)
This is the mistake when one accepts the null hypothesis (there is no effect) when it is false (there really IS an effect). This is also called a false negativefailure to detect a real effect. (see 3.162 false negative.)
individual fibers from a technical fiber (see3.2.53).
Individual fibers from a technical fiber (see technical fiber)
Electromagnetic radiation with a wavelength from 100 nm (30 PHz) to 380 nm (750 THz), which, when used as a light source, can fluoresce dental materials for better visualization and location.
(1) areas on storage media which a file system has marked as available for use for data storage; (2) the portions of storage media that are unassigned external to a file system. DISCUSSIONThe area may already contain previously stored infor- mation. Also referred to as free space.
(1) areas on storage media which a file system has marked as available for use for data storage; (2) the portions of storage media that are unassigned external to a file system
See classical conditioning.
An alert for which the presence of a trained odor/scent cannot be confirmed. This may be the result of residual or lingering odor/scent that the canine can detect but which has not been confirmed by technology or direct observation. (See non-productive response.)
Lack of verification of search results following a deployment of a canine team(s).
Lack of verification of search results following a deployment of a canine team(s).
Lack of verification of search results following a deployment of a canine team(s).
Lack of verification of search results following a deployment of a canine team(s)
Lack of verification of search results following a deployment of a canine team(s)
Lack of verification of search results following a deployment of a canine team(s)
In facial identification, an image not captured in accordance with facial identification/facial recognition (FI/FR) standards or guide- lines (for example, a surveillance image).
In facial identification, an image not captured in accordance with facial identification/facial recognition (FI/FR) standards or guidelines (for example, a surveillance image). (See image.)
A written or oral consensus between the interested parties concerning the management of the investigations.
A computing industry standard for the representation of most of the world's scripts (suchas Latin letters, Cyrillic letters, Chinese characters, special symbols and others). See A.
The smallest group of atoms of a crystal lattice that has the overall symmetry of a crystal of that substance, and from which the entire lattice can be built up by repetition in three dimensions.
An individual heel or outsole that must be glued and/or stitched to the upper.
Measures taken to ensure safety under the assumption that any unknown materials or situations present the most dangerous scenario possible.
Data that cannot be used for comparisons for reasons including, but not limited to, poor or limited data quality, mixture complexity, or a failure to meet quality assurance requirements.
Rubber not subjected to the process of vulcanization. The handling of this material may result in randomly acquired characteristics.