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.
The column of hot gases, flames, and smoke rising above a fire; also called convection column, thermal updraft, or thermal column.
Portable Network Graphics.
The physical location within the area of origin where a heat source, a fuel, and an oxidizing agent first interact, resulting in a fire or explosion.
An open area search method in which the canine team moves in a straight line from one designated location (point) to another.
Viewing a sample on a compound microscope that has been fitted with special filters that orient the light rays, providing analytical information about the sample.
A process whereby a document is sealed between two sheets of polyester film to preserve, stabilize, and facilitate handling.
A process whereby a document is sealed between two sheets of polyester film to preserve, stabilize, and facilitate handling.
An enzyme that catalyzes the synthesis of nucleic acids on preexisting nucleic acid templates.
An enzyme that catalyzes the synthesis of nucleic acids on preexisting nucleic acid templates.
An enzymatic process by which a specific region of DNA is replicated during repetitive cycles that consist of the following: denaturation of the template; annealing of primers to complementary sequences at an empirically determined temperature; and extension of the bound primers by a DNA polymerase. The goal of the PCR process is to generate many copies (termed products or amplicons) of a specific region of DNA for further analysis.
An enzymatic process by which a specific region of DNA is replicated during repetitive cycles that consist of the following: denaturation of the template; annealing of primers to complementary sequences at an empirically determined temperature; and extension of the bound primers by a DNA polymerase. The goal of the PCR process is to generate many copies (termed products or amplicons) of a specific region of DNA for further analysis.
An enzymatic process by which a specific region of DNA is replicated during repetitive cycles that consist of the following: denaturation of the template; annealing of primers to complementary sequences at an empirically determined temperature; and extension of the bound primers by a DNA polymerase. The goal of the PCR process is to generate many copies (termed products or amplicons) of a specific region of DNA for further analysis.
The analytical process by which targeted segments of DNA are replicated during repetitive cycles of heating to denaturation, and cooling to anneal primer oligonucleotides and extend DNA sequences to enhance detection of DNA fragments.
An enzymatic process by which a specific region of DNA is replicated during repetitive cycles that consist of the following: denaturation of the template; annealing of primers to complementary sequences at an empirically determined temperature; and extension of the bound primers by a DNA polymerase. The goal of the PCR process is to generate many copies (termed products or amplicons) of a specific region of DNA for further analysis.
An enzymatic process by which a specific region of DNA is replicated during repetitive cycles that consist of the following: denaturation of the template; annealing of primers to complementary sequences at an empirically determined temperature; and extension of the bound primers by a DNA polymerase. The goal of the PCR process is to generate many copies (termed products or amplicons) of a specific region of DNA for further analysis.
The occurrence in a population of two or more alleles or physical traits at a genetic locus. This variation within a population permits the differentiation of individuals via DNA testing or physical traits.
crystallization into two or more chemically identical but crystallographically distinct forms.
The occurrence in a population of two or more alleles or physical traits at a genetic locus. This variation within a population permits the differentiation of individuals via DNA testing or physical traits.
Dental casting material formulated to render fine detail.
A group of organisms of the same species in a defined geographic area, such that any pair of members can interbreed.
A group of organisms of the same species in a defined geographic area, such that any pair of members can interbreed.
A group of organisms of the same species in a defined geographic area such that any pair of members can interbreed.
Individuals grouped by shared factors such as geography, biology, culture, language, etc.
A measure (e.g., distance, probability of membership) of similarity between the individual and reference groups (see Annex A).
The study of genes and allele frequencies in populations.
The existence of subpopulations with different allele frequencies.
Assignment of tooth numbers based upon the location of the teeth. This is in contrast tomorphological tooth numbering, which assigns a tooth number based upon position,the shape of the tooth. For most cases, the tooth number assignment would be the same.Differences arise only in unusual cases.
A trained detection alert in the presence of the target odor/scent.
A trained detection alert in the presence of the target odor/scent.
A trained detection alert in the presence of the target odor/scent.
A trained detection alert in the presence of the target scent
A trained detection alert in the presence of the target scent
A test sample like the case sample(s) that contains the analyte(s) of interest at a known concentration
An analytical control sample that is used to determine if a test performed properly; this control consists of the test reagents and a known sample that will provide an expected positive response with the test. NOTE For DNA testing, positive controls include positive amplification controls and may include extraction positive controls.