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.
An electrophoretic technique for separating DNA molecules by their relative size based on their differential migration through a capillary tube filled with a liquid polymer.
An electrophoretic technique for separating DNA molecules by their relative size based on their differential migration through a capillary tube filled with a liquid polymer.
An electrophoretic technique for separating DNA molecules by their relative size based on their differential migration through a capillary tube filled with a liquid polymer.
An electrophoretic technique for separating DNA molecules by their relative size based on their differential migration through a capillary tube filled with a liquid polymer
to record data, such as an image, video sequence, audio stream, or biometric sample to digital storage, often by means of a sensor.
appearance of unintended analyte signal in samples after the analysis of a positive sample
The appearance of unintended analyte signal in samples after the analysis of a positive sample
forensic service provider’s records detailing the forensic process including reports related to a case
A type of file (electronic or hard copy) in which all documentation and case relevant information is kept and maintained.
A type of file (electronic or hard copy) in which all documentation and case relevant information is kept and maintained.
Data exhibiting features that are representative of a plausible range of casework conditions for mixtures and single-source samples. These features include masked/shared alleles and stutter, degradation (including different degradation levels for different contributors to a mixture), allele and locus drop-out, and PCR inhibition
Samples from known individuals with known testing results prepared within the laboratory to simulate a range of samples typically encountered by the testing laboratory in casework. The use of a range of test samples in validation studies facilitates the development of protocols for casework.
Samples from known individuals with known testing results prepared within the laboratory to simulate a range of samples typically encountered by the testing laboratory in casework. The use of a range of test samples in validation studies facilitates the development of protocols for casework.
Biological material obtained from a known individual and collected for purposes of comparison to unknown samples.
Biological material of unknown origin recovered from the crime scene or believed to have originated from an individual of interest that may be associated to a crime.
A method of preserving and recovering an impression utilizing an appropriate casting material.
(1) A description of the canine's movement as the canine searches for and/or follows the concentration of target odor/scent. (2) A directional command to the canine.
Dental stone, snow print powder, sulfur, or other suitable materials specifically used to accuratelyrecover three-dimensional impressions. Some casting materials are also successful for lifting twodimensional impressions.
Dental stone, snow print plaster, sulfur, or other suitable materials specifically used to accuratelyrecover three-dimensional impressions. Some casting materials are also successful for lifting twodimensional impressions.
Partial or complete clouding of the lens on the eye that leads to a decrease in vision. Cataracts can be genetic or acquired.
Partial or complete clouding of the lens in the eye that leads to a decrease in vision. Cataracts can be genetic or acquired.
opinion that, in the examiner’s judgement, one proposition or explanation is true and it would be impossible to obtain the observations if any of the alternative propositions or explanations considered were true
EXAMPLE 1:In the examiner’s judgement, the shoe did not make the questioned shoemark.
EXAMPLE 2:In the examiner’s judgement, the cartridge case is of Smith and Wesson brand.
The circumstances, conditions, or agencies that brought about or resulted in the fire or explosion incident, damage to property, bodily injury, or loss of life.
A medical opinion stating which disease, injury, or physiological derangement was responsible for initiating the lethal sequence of events that resulted in an animal’s death.
Medical opinion of the disease or injury that resulted in a person’s death.
A medical opinion of the disease or injury that resulted in a person's death.
Common Biometric Exchange Formats Framework. It provides a set of definitions usedto exchange biometric data in a standardized manner. It forms the basis for Type-99records.
Committee to Define an Extended Fingerprint Feature Set.
A relatively thin layer of flowing hot gases that develops under a horizontal surface (e.g., ceiling) as a result of plume impingement and the flowing gas being forced to move horizontally.
A buoyant layer of hot gases and smoke produced by a fire in a compartment.