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.
Irregularity or abnormality of the cornea, the clear outermost layer of the eye.
Irregularity or abnormality of the cornea, the clear outermost layer of the eye.
An elected or appointed official whose duty is to oversee medicolegal death investigations, usually for a single county, and ensure certification of cause and manner of death; duties vary based on local enabling statutes.
An elected or appointed official responsible for overseeing medicolegal death investigations, usually for a single county, and for certifying the cause and manner of death in these investigations; duties vary based on local enabling statutes.
The application of an aversive stimulus intended to prompt the canine to cease undesired behavior using verbal reprimand, choke collar (slip)/check chain, prong collar, remote trainer, etc.
Action to eliminate or mitigate the cause of a non-conformity and to prevent recurrence. NOTE A corrective action is taken to prevent recurrence whereas a preventive action is taken to prevent occurrence.
A training course of action to remediate performance deficiencies with a canine team.
A training course of action to remediate performance deficiencies with a canine team.
A training course of action to remediate performance deficiencies with a canine team.
A training course of action to remediate performance deficiencies with a canine team.
A correlation is an association between two variables, when the variables are related. Correlation does not imply cause.
the primary anatomical region of a hair between the cuticle region and the medullary region composed of elongated and fusiform cells.
the main structural component of hair consisting of elongated and fusiform (spindle-shaped) cells; the cortex can contain pigment granules, air spaces called cortical fusi, and structures called ovoid bodies.
small air spaces that form between the cortical cells in the hair shaft and, under transmitted light, appear as tiny, dark structures.
the relief or definition of the margins of the cortical cells when viewed using transmitted light microscopy.
(see 2.35 undetermined)
in knitted fabrics, a row of successive loops in the width direction of the fabric.
The analysis of specimens from subjects within the judicial system or part of an active investigation to determine the presence or absence of drugs or other chemical substances.
The tendency of a material to move or deform permanently to relieve stresses.
paper that has small folds in it giving it high stretch and conformability. Used in the backing of masking tape (saturated paper tape).
a branch of forensic science concerned with the examination and interpretation of physical evidence, for the purpose of aiding forensic investigation.
the curl, wave, or compression that is naturally occurring or otherwise imparted to a fiber.
A point at which mental or physical duress causes survival and trainability to come into conflict.
Chemicals or other materials used in testing whose performance is vital to the success of the test as determined by empirical studies or routine practice.
Chemicals or other materials used in testing whose performance is vital to the success of the test as determined by empirical studies or routine practice.
Any software or modification that directly affects the integrity of the evidence, the analytical process, interpretations, statistical conclusions, case file documentation, chain of custody documentation, accuracy of results, report wording, or any other item deemed integral.
A change in the canine's behavior where the canine becomes distracted by animal odor or some other animal distracter. Usually evident as there is a change in body language (head and tail position). (See distractibility.)
The opportunity for the attorney (or an unrepresented party) to ask questions of a witness who has been called to testify by the opposing party.
See contamination.
A path where something can be crossed to get from one side to the other.
the shape of a hair shaft when cut at a right angle to its longitudinal axis.
Discussion—When viewed longitudinally with transparent light, the apparent cross-sectional shape is determined by slowly focusing through the hair (optical cross-sectioning). When viewed longitudinally between crossed polars, the cross-sectional shape can be determined by observing the interference colors.
the raised portion of a strand in twisted cordage.
a naturally occurring mixture of gaseous, liquid, and solid hydrocarbon compounds usually found trapped deep underground beneath impermeable cap rock and above a lower dome of sedimentary rock such as shale.
The absence of one or both testes from the scrotum.
The absence of one or both testes from the scrotum
a homogeneous, solid body of a chemical element or compound, having a regularly repeating atomic arrangement that can be outwardly expressed by plane faces.
the three-dimensional regularly repeating set of points that represent the translational periodicity of a crystal structure.
Discussion—Each lattice point has identical surroundings. Lattice is the abstract pattern used to describe the internal geometric structure of crystals. Lattice and structure are not synonymous, as structure refers to the real mineral material.
having a crystal structure or a regular arrangement of atoms in a crystal lattice.
Perception of the near infallibility of forensic science in response to popular media.
Computerized tomography scan.
A verbal or physical action (done consciously or unconsciously) by anyone, and/or any environmental stimulus that causes a detector canine to change its actions to respond to an area or item whether target odor/scent is present or not.
An assemblage of biological reference materials acquired and maintained with associated data according to explicit quality control standards.
the temperature at which a ferromagnetic metal loses its ferromagnetic properties.
A flow of electric charge.
Data for the individual in his/her current state, not necessarily data recorded or createdon the current date. For instance, current data on a subject may be a radiograph of adecedent taken at the time of burial several years ago that is now being compared toradiographs that had been provided for a missing person prior to the assumed date ofdeath of the subject.
Client, authority, organization, or person(s) requesting the forensic services.
the outermost region of a hair composed of layers of overlapping scales.
Discussion—The dimension of the cuticle as measured from its outer margin to the cortex is often described in relative terms (for example, thin, medium, thick).
in mammalian hair fibers, the layers of flattened cells enclosing the cortex, which form an envelope of overlapping scales surrounding the fiber.
a cuticle with linear breaks that are perpendicular to the length of the shaft.