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.
A short polynucleotide chain, usually 1830 bases long, which targets a specific region of the template DNA and allows a DNA polymerase to initiate synthesis of a complementary strand; two primers are required for amplification of a particular section of double-stranded DNA. The primers are complementary to opposite strands and are designed to bracket the region of interest for amplification. Polymerization is initiated at the 3' end of the primer and extends in a 5 to 3 manner.
A short polynucleotide chain, usually 18-30 bases long, which targets a specific region of the template DNA and allows a DNA polymerase to initiate synthesis of a complementary strand; two primers are required for amplification of a particular section of DNA. The primers are complementary to opposite strands and are designed to bracket the region of interest for amplification. Polymerization is initiated at the 3' end of the primer and extends in a 5 to 3 manner.
ignition component of a cartridge.
Discussion—Commonly, a mixture of initiator, sensitizer, oxidant, fuel, and frictionator.
a metal or plastic cap that contains a small amount of initiating explosive, which is readily ignited by shock.
Discussion—Primer caps (also referred to as simply ‘primers’) serve as the igniting element in small arms cartridges.
that portion of GSR resulting from the explosion of the primer compounds.
Print data includes writings, drawings, graphs, charts, photographs, images, and other material in paper or print form, including ESI that has been reproduced on paper or print media.
Data collected when the subject was in a different, previous state/condition than thecurrent state of the subject. Examples are antemortem data, when postmortem dataexists or facial images of a missing person that are compared to those of the personbeing interviewed.
the direction of vibration to which light emerging from a polarizer has been restricted.
Discussion—In modern microscopes, the polarizer’s privileged direction is oriented in the east-west direction and the analyzer’s privileged direction is oriented in the north-south direction.
The use of biological modeling (i.e., statistical modeling informed by biological data), statistical theory, computer algorithms, and/or probability distributions to infer genotypes and/or calculate likelihood ratios
Software, or software and hardware, which utilizes a probabilistic genotyping approach to infer genotypes and/or calculate likelihood ratios
A quantified measure between zero and one indicating how probable or likely it is that an event will or has occurred. In the frequentist interpretation, probability is based on the rates at which events occur. In the Bayesian interpretation, probability reflects a degree of belief. On this scale, zero indicates impossibility and one indicates absolute certainty.
Probable cause exists when the facts and circumstances known to the officer would warrant a prudent person to believe a crime had been committed and the accused had committed it or that the evidence will be found in the place to be searched.
in facial identification, a facial image or template searched against the gallery in a facial recognition (FR) system.
Specified way to carry out an activity or a process. 1) Procedures can be documented or not. 2) When a procedure is documented, the term written procedure or documented procedure is frequently used. The document that contains a procedure can be called a procedure document.
specified way to carry out an activity or a process.
Discussion—(1) Procedures can be documented or not. (2) When a procedure is documented, the term “written procedure” or “documented procedure” is frequently used. The document that contains a procedure can be called a “procedure document.”
Set of interrelated or interacting activities which transforms inputs into outputs
set of interrelated or interacting activities which transforms inputs into outputsNOTE Adapted from ISO 9000:2005, definition 3.4.1.
an analytical control that is derived from the labware, reagents, and solvents used in various stages of this procedure to check for interfering or contamination products introduced by labware or solvents.
A control to test a analytical process such as hydrolysis or oxidation of an analyte
Ordinate values that have been processed (e.g., trimmed, filtered, and/or interpolation applied).
in image and video analysis, any image that has undergone enhancement, restoration, or other operation.
Results of a process
result of a processNOTE 1 Four generic product categories are noted in ISO 9000:2005:- services (e.g. transport) (see definition in 3.4);- software (e.g. computer program, dictionary); - hardware (e.g. engine, mechanical part);- processed materials (e.g. lubricant).Many products comprise elements belonging to different generic product categories. Whether the product is then calledservice, software, hardware or processed material depends on the dominant element.NOTE 2 Products include results of natural processes, such as growth of plants and formation of other naturalresources.NOTE 3 Adapted from ISO/IEC 17000:2004, definition 3.3.
See combustion products.
A change of behavior of the canine followed by a positive indication that can be confirmed by the canine handler.
A change of behavior of the canine followed by a positive indication that can be confirmed by the canine handler.
in forensic audio and video analysis, a device or software or both used to mix video or audio signals or both from two or more sources. (Compare routing switcher.)
the mechanism through which a forensic science practitioner improves personal skills, successfully handles increasing responsibility, makes contributions to the profession, and reinforces ethical behaviors.
An evaluation during training; a tool to assess a canine team's ability.
evaluation of participant performance against pre-established criteria by means of interlaboratory comparisons.
Also referenced in ASTM E1732-24ae1 Standard Terminology Relating to Forensic Science, ANSI/ASTM E1301-95 Standard Guide for Proficiency Testing by Interlaboratory Comparisons, ANSI/ASB Standard 153 Standard Practices for Proficiency Testing for Forensic Toxicology Laboratories and Breath Alcohol Programs.
Single complete sequence of distribution of proficiency test items, and the evaluation and reporting of the results to the participants. (Source: ISO/IEC 17043:2010, 3.10)
Proficiency testing designed and operated in one or more rounds for a specified area of testing, measurement, calibration or inspection. (Source: ISO/IEC 17043:2010, 3.11)
All-encompassing plan of action aimed at accomplishing a clear objective that meets a defined need. i.e. the instruction for completing the training, certification, and documentation requirements within a detection canine discipline.
in computer forensics, a list of coded instructions causing a computer to perform a specific task or set of tasks.
in video analysis, a display scan pattern in which each line of the frame is scanned out sequentially.
A previously learned association that stimulates the initiation of a response. Instructions, gestures, physical guidance and modeling cues serve as prompts to the canine.
A training technique that aims to teach the canine to ignore all odors/scents except target odors/scents.
a compressed gas used to expel the contents of containers in the form of aerosols.
any file format that is unique to a specific manufacturer or product.
Awareness of the relative body position in space at rest and during movement.
An established practice to be followed in performing a specified task or under specific circumstances
A description of the specific procedures and methodologies by which a task or tasks are to be accomplished.
in computer forensics, a set of conventions governing the format and timing of message exchanges to control data movements and correct errors.
a place or origin; specifically, the area from which the constituent materials of a sedimentary rock or facies are derived, also, the rocks of which this area is composed.
Discussion—In the context of forensic provenance examination, geological material is analyzed and interpreted to estimate or limit the geographic or environmental conditions of the source of this material to provide an investigative lead. For example, soil on a shovel can be examined to aid in the search for a clandestine grave, typically by comparison of observations to reference data. "Geographic attribution" is an alternative term for provenance.
a place of origin; specifically, the area from which the constituent materials of a sedimentary rock or facies are derived.
Discussion—In the context of forensic provenance analysis, geological material is analyzed and interpreted to estimate or limit the geographic or environmental conditions of the source of this material to provide an investigative lead. For example, soil on a shovel can be examined to aid in the search for a clandestine grave, typically by comparison of observa- tions to reference data. Geographic attribution is an alternative term for provenance.
The cause that directly produces the effect without the intervention of any other cause.
the portion of the hair closest to, and including, the root.