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.
In audio and video analysis, the process of determining the most suitable equipment and settings for producing the highest quality output signal.
In audio and video analysis, the process of determining the most suitable equipment and settings for producing the highest quality output signal
The property of exhibiting different colors, especially three different colors, when viewed along different axes by plane polarized light. The phenomenon of substances showing different absorption colors in different vibration directions. The observed colors change with the orientation of the crystal and can be seen only with plane polarized light
Crystals resembling pliers, generally X-shaped.
Crystals resembling pliers, generally X-shaped
The column of hot gases, flames, and smoke rising above a fire; also called convection column, thermal updraft, or thermal column.
(1) the number of single yarns twisted together to form a plied yarn, or the number of plied yarns twisted together to form cord; (2) an individual yarn in a plied yarn or cord; (3) one of a number of layers of fabric; (4) the number of layers of fabric as a shirt collar, or of cord in a tire.
Rubber-coated parallel cord fabric placed over the liner forming the tire carcass.
(1) the number of single yarns twisted together to form a plied yarn, or the number of plied yarns twisted together to form cord; (2) an individual yarn in a plied yarn or cord; (3) one of a number of layers of fabric; (4) the number of layers of fabric as a shirt collar, or of cord in a tire
A tire filled with air under pressure.
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.
a bundle of light rays with a single propagation direction and a single perpendicular vibration direction.
A bundle of light rays with a single propagation direction and a single perpendicular vibration direction
A microscope equipped with two polarizing filters, one below the stage (the polarizer) and one above the stage (the analyzer)
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.
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.
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.
hydrocarbon consisting of two or more fused aromatic rings.
A polyester or polyether-based polymer used in both the outsoles and midsoles of footwear.
A thermoplastic polymer used in footwear outsoles.
Dental casting material formulated to render fine detail.
Dental casting material formulated to render fine detail.
The totality of items or units of material under consideration. The word items may be interpreted in the sense of measurements, or possible measurements, of a single characteristic, or occasionally for multiple characteristics, on all items or units of material being considered. The word totality may refer to items not available for inclusion in samples as well as those which are available.
The totality of items or units of material under consideration
A group of organisms of the same species in a defined geographic area, such that any pair of members can interbreed.
Experiments performed to determine the effectiveness and utility of the test with representative samples from the population.
In facial identification, the orientation of the face with respect to the camera, consisting of pitch, roll, and yaw.
In facial identification, the orientation of the face with respect to the camera, consisting of pitch, roll, and yaw
The location and direction of an area of erosion on a footwear outsole or tire tread. Examples of location of wear include wear along the medial edge of the footwear outsole and wear along the outer edge of a tire tread. The position and orientation of wear can change as a footwear outsole or tire tread is worn.
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 material of established origin that is used to confirm that a procedure will produce the expected result.
A test sample like the case sample(s) that contains the analyte(s) of interest at a known concentration
See transfer impression.
An integer greater or equal to 1. The value 0 is not included in this use of the term.
A type of search conducted in a specific area in which an existing human scent in the environment matches that of the scent article presented to the canine.
A type of search conducted in a specific area in which an existing human scent in the environment is associated with the scent article presented to the canine.
Within this document the positive predictive value is defined as the fraction of identifications that correspond to true known matches, TP/(TP+FP) where TP (True Positives) is the number of correctly identified Known Matches and FP (False Positives) is the number of Known Non-Matches incorrectly determined to be an Identification.
A reward given after a response or as the response occurs that increases the probability of that response recurring. For example, if a canine is rewarded for sitting by being given a treat the canine is more likely to sit again.