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.
Clarification
Clarify
clarity
Assessment of the quality of a friction ridge impression, describing an examiner’s opinion as to how easily the friction ridge feature are visually observed in an impression. Sometime referred to as an examiner’s confidence in the presence of an observed feature, that can be discerned from the background.
Class
Class Characteristic
class defect common defect
A deviation from a class characteristic that is present in a similar, but not necessarily exact, manner in a significant number, even most, but not all, of the members of a class or subclass.
Class Resolution
The value of resolution (scanning or nominal) used to name (or identify) an acquisitionprocess or image, where the resolution is within a specified tolerance around that value.Example: A scanner is referred to as 500 ppi (class resolution) if the native scanningresolution is within 1% (5 ppi).
Classical (Pavlovian) Conditioning
A form of learning in which the pairing of a previously neutral stimulus with a stimulus that elicits a response results in that neutral stimulus producing a similar response
Classification
Classification
Clean Burn
A distinct and visible fire effect generally apparent on noncombustible surfaces after combustible layer(s) (such as soot, paint, and paper) have been burned away.
Clean Room, Clean Chamber, Positive Air Flow Cabinet
Clear
Clicker
client
person or organization requesting inspection (3.1) of an item (3.8)
Note 1 to entry: The client can be different from the provider of the item.
clinical veterinary forensic examination
Medical evaluation by a veterinarian of a live animal for medicolegal purposes.
NOTE The examination may include, but is not limited to, the assessment of behavior, body condition score and organ systems to identify and document an animal's overall condition at a point in time.
closed loop
A loop formation that approximates a retrace, where the sides of the loop run parallel together.
Cluster
Co-Ordination/Timing
The canine handler's ability to correctly recognize and reward a desired behavior of the canine, or redirect or stop an undesired behavior.
coalescence
A model in population genetics to describe a process of how gene variants sampled from a population may have originated from a common ancestor.
coalescence
Puddling or pooling of adjacent ink drops on the substrate before they can be dried or absorbed resulting in non-uniformity of color density. (ASTM F1857- Withdrawn 2020)
Coating
a generic term for paint, lacquer, enamel, or other liquid or liquefiable material that is converted to a solid, protective, or decorative film or a combination of these types of films after application.
Coaxial Light
Cocaine
cockle
Of paper, a defective, puckered condition of a paper sheet as a result of nonuniform hygroexpansion which can be related to any nonuniformity in the sheet, including mass distribution and drying stresses. (ASTM D1968)
Code
A standard that is an extensive compilation of provisions covering broad subject matter or that is suitable for adoption into law independently of other codes and standards.
Codec
A codec is a computer program that encodes and decodes a data signal, usually in acompressed format.
Codec
Algorithm designed to encode or decode a stream of digital audio data.
Codec
Codec Format
A codec format is the data structure produced by a codec.
CODIS
An acronym for the Combined DNA Index System administered by the FBI. There are three levels of CODIS: the Local DNA Index System (LDIS), used by individual laboratories; the State DNA Index System (SDIS), used at the state level to serve as a state’s DNA database, and the National DNA Index System (NDIS), managed by the FBI as the nation’s DNA database containing all DNA profiles uploaded by participating states.
CODIS administrator(s)
An employee of a participating federal, state, or local criminal justice agency responsible for administration and security of the laboratory’s CODIS at a laboratory performing DNA analysis on database, forensic, or casework reference samples.
CODIS core loci
An established set of short tandem repeat (STR) loci required to be tested for inclusion of a DNA profile in CODIS.
coefficient of co-ancestry
The probability that two alleles randomly sampled from different individuals are copies of the same ancestral allele without mutation, that is, the probability that they are identical by descent.
Coercion Training
Coercion deals with compliance induced by physical or mental pressure. Examples may include use of force, threats, or intimidation.
Cognitive Image Analysis
Coherence Scanning Interferometry
Surface topography measurement method wherein the localization of interference fringes during ascan of optical path length provides a means to determine a surface topography map.
Coherent (Rayleigh) Scatter Peaks
coincidental peripheral printing
Resulting from an impression of unintended printing areas, often on the periphery, of a stamp. This may be due to the manufacturing process or the stamping technique. (SWGDOC E10)
collapsed side
Occurs in the formation of the cursive letters “m” and “n” when the left or right arcade is formed as a retrace or near retrace movement.
collate
1) Analyze and compare to identify points of agreement and difference; critical comparison or side by side examination.
2) Arrange paper in the proper sequence, such as by photocopiers.
collected writing
A subset of known writing. Samples of a known person’s handwriting/signatures that have been produced throughout the course of day-to-day business, are typically not related to the case at hand, and have been collected for the purposes of comparison against questioned material. Examples include letters, diaries, business records, forms, or checks. These are also known as normal course specimens, course of business specimens, or undictated writing.
collected writing handwritten standard
A subset of known writing. Samples of a known person’s handwriting/signatures that have been produced throughout the course of day-to-day business, are typically not related to the case at hand, and have been collected for the purposes of comparison against questioned material. Examples include letters, diaries, business records, forms, or checks. These are also known as normal course specimens, course of business specimens, or undictated writing.
Color Contrast
Color contrast classes
Color Range
color-shifting ink
An ink that reflects various wavelengths of white light differently, depending on the angle of incidence to the surface.
Combustible
Combustible
Combustible
Capable of undergoing combustion.