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 cartridge case containing only a primer, without propellant or projectile.
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.
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.
ignition component of a cartridge.
Discussion—Commonly, a mixture of initiator, sensitizer, oxidant, fuel, and frictionator.
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 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 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.
Short polynucleotide sequences which target a specific region of template DNA and allow a DNA polymerase to initiate synthesis of a complementary strand.
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.
Portions of impression designating certain non-numeric designations located to the right of the first numeric segment.
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.
Autopsy requested and authorized by next of kin.
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.
Possessing the potential to provide information that may be valuable to an investigation.
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.”
An established practice to be followed in performing a specified task.
set of interrelated or interacting activities which transforms inputs into outputsNOTE Adapted from ISO 9000:2005, definition 3.4.1.
Set of interrelated or interacting activities which transforms inputs into outputs
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.
Person, authorized by the certification provider, who administers or supervises a certification test, but does not evaluate the competency of the candidate.
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.
Results of a process
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.)
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.
See combustion products.
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.
A defect or feature that appears during the use of the stamp and can change with additional usage.
in video analysis, a display scan pattern in which each line of the frame is scanned out sequentially.
A skeletal defect often produced by high-velocity impact over a relatively small surface area, typically by projectiles from firearms, but can result from any small object impacting a bone at a high velocity.
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.