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 visible concentration of sample applied to the TLC plate; also known as the origin.
Applying a solute sample at the origin of the TLC plate
An analytes resistance to chemical change in a matrix under specific conditions for given time intervals
A compound to prevent or slow down self-decomposition
analyte’s resistance to chemical change in a matrix under specific conditions for given time intervals
A location separate from the search site designated for canine handlers to wait until they are called to search.
Material of established origin with certified properties
An established or widely recognized model of authority or excellence as a reference point against which other things can be evaluated or the ideal in terms of which something can be judged.
An NFPA Standard, the main text of which contains only mandatory provisions using the word 'shall' to indicate requirements and that is in a form generally suitable for mandatory reference by another standard or code or for adoption into law. Nonmandatory provisions are not to be considered a part of the requirements of a standard and shall be located in an appendix, annex, footnote, informational note, or other means as permitted in the NFPA Manuals of Style. When used in a generic sense, such as in the phrase 'standards development process' or 'standards development activities,' the term 'standards' includes all NFPA Standards, including Codes, Standards, Recommended Practices, and Guides.
An NFPA Standard, the main text of which contains only mandatory provisions using the word 'shall' to indicate requirements and that is in a form generally suitable for mandatory reference by another standard or code or for adoption into law. Nonmandatory provisions are not to be considered a part of the requirements of a standard and shall be located in an appendix, annex, footnote, informational note, or other means as permitted in the NFPA Manual of Style. When used in a generic sense, such as in the phrase 'standards development process' or 'standards development activities,' the term 'standards' includes all NFPA Standards, including Codes, Standards, Recommended Practices, and Guides.
material of established origin with certified properties. E1732
DISCUSSION—For the purposes of fire debris analysis, this term is used for materials with a certificate of analysis from the supplier reporting the results of their characterization.
In video analysis, the transformation of one television system signal to another, for example, National Television System Committee (NTSC) to Phase Alternating Line (PAL)
In video analysis, the transformation of one television system signal to another, for example, National Television System Committee (NTSC) to Phase Alternating Line (PAL).
Investigator's tools and equipment that every investigator must carry.
A method published by a recognized international, regional, or national standard devel- opment organization (for example, ASTM, ASB, AOAC, etc.).
Written documentation maintained by the laboratory including laboratory policies, technical protocols and methods for specific forensic analyses (see also technical procedure).
Written analytical procedure that describes how to perform certain organization activities
Natural fibers or cut lengths from filaments
natural fibers or cut lengths from filaments.
A 5-bit binary sequence, or equivalent ASCII character, used to signify the beginning of track data
A 5-bit binary sequence, or equiva- lent ASCII character, used to signify the beginning of track data. (See ISO/IEC 7813:2006.)
A 5-bit binary sequence, or equiva- lent ASCII character, used to signify the beginning of track data. (See ISO/IEC 7813:2006.)
A largely unconscious defensive response to sudden or threatening stimuli or perceived stimuli.
A largely unconscious defensive response in a canine to sudden or threatening stimuli or perceived stimuli.
see static headspace sampling (E1388), and static headspace concentration
see static headspace sampling (E1388), and static headspace concentration (E3189).
An extraction technique in which a portion of the headspace vapors is removed from the sample container
an extraction technique in which a portion of the headspace vapors is removed from the sample container
An extraction technique in which a portion of the headspace vapors is removed from the sample container and concentrated onto an adsorbent medium
an extraction technique in which a portion of the headspace vapors is removed from the sample container and concentrated onto an adsorbent medium.
an extraction technique in which a portion of the headspace vapors is removed from the sample container and concentrated onto an adsorbent medium.
an extraction technique in which a portion of the headspace vapors is removed from the sample container.
an extraction technique in which a portion of the headspace vapors is removed from the sample container
The solid adsorbent coating layer of a TLC plate
the solid adsorbent coating layer of a TLC plate.
The probability of obtaining the observed resultor a more exaggerated oneif the null hypothesis of no effect was true.
A Category 2 scoring function.
A classical technique used to separate and concentrate ignitable liquid residues from fire debris samples by boiling the sample in water and condensing the vapors in order to recover the higher boiling point fraction. ASTM E 1385 is the historical standard describing this technique.
Technique for embedding information into something else, such as a text file in an image or a sound file, for the sole purpose of hiding the existence of the embedded information
A microscope containing two separate optical paths, one for each eye, giving a three-dimensional view of a specimen
a microscope containing two separate optical paths, one for each eye, giving a three-dimensional view of a specimen.
The act of producing a snoring sound.
The act of producing a snoring sound [1].
A friction ridge image created by combining images that were separately captured.
1) Chance, or random variation 2) in DNA testing, refers to random sampling error from extracts containing low levels of DNA and/or random variation in selection of alleles amplified at a particular locus.
Changes in a DNA profile that generally occur when suboptimal or limiting quantities of DNA are tested. This may be due to sampling variation (e.g., pipetting) of the target DNA that goes into the ANSI/ASB Standard 020, 1st Ed. 2018 2 polymerase chain reaction (PCR) and/or random events between primers and target DNA during PCR amplification. The effects may be observed at one or more loci, and include: 1) peak height imbalance of sister alleles in a heterozygous pair; 2) loss of data (referred to as 'allele drop out' when one or more alleles are missing at a locus and 'locus drop out' when all alleles are missing from a locus); 3) allele drop-in (allelic peak(s) in an electropherogram that are not reproducible); and 4) elevated stutter peaks