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.
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 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 (a non-allelic peak in the stutter position exceeding the stutter expectation of the laboratory).
Changes in a DNA profile that generally occur when suboptimal or limiting quantities of DNA are tested.
NOTE This may be due to sampling variation (e.g., pipetting) of the target DNA that goes into the 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 (a non-allelic peak in the stutter position exceeding the stutter expectation of the laboratory).
in computer forensics, retrievable retention of data; electronic, electrostatic, or electrical hardware or other media into which data may be entered, and from which data may be retrieved.
any object on which data is preserved.
Short sequences of DNA that are repeated numerous times in direct succession. The numberof repeated units may vary widely between individuals and this high level of variationmakes STRs particularly useful for discriminating between people. The person to whom the data in the record applies. The subject of the record need notbe the subject of the transaction.
(1) a single fiber, filament, or monofilament; (2) an ordered assemblage of textile fibers having a high ratio of length to diameter and normally used as a unit; includes slivers, roving, single yarns, plied yarns, cords, braids, ropes, etc.
Discussion—A strand is often multiple plies joined together. The terms “ply” and “strand” are not synonymous; cordage can have a single-plied strand, but not a stranded ply.
A harsh vibrating sound heard during respiration in cases of obstruction of the air passages.
A harsh vibrating sound heard during respiration in cases of obstruction of the air passages.
Surface topography measurement method whereby a light image with a known structure or patternis projected on a surface and the pattern of reflected light together with knowledge of the incidentstructured light allows one to determine the surface topography.
The anatomical correctness of the feet and legs of an animal.
sample device with an adhesive surface used to collect materials for SEM/EDS analysis.
in computer forensics, a directory object contained within another directory object in a filesystem.
a group of fibers within a generic class that share the same base-polymer composition; sub-generic names include, for example, nylon 6 and nylon 6,6.
in facial identification, the facial image capture criteria described in ANSI/NIST-ITL 1-2011.
The person to whom the transaction applies. The subject of a record need not be thesubject of the transaction.
The placement of a document(s) into a liquid to facilitate cleaning, unfolding, or separation of the document(s).
Willingness of the canine to yield to or cede control to a handler, another person or animal.
An order of the court for a witness to appear at a particular time and place to testify and/or produce documents in the control of the witness.
Recognition and response to trained target odor.
Surface upon which a friction ridge impression is deposited.
The placement of human remains under ground or surface area, i.e., buried or underwater
A decision made by an examiner in accordance with FSP policy and/or procedure as to whether or not an impression will proceed to the next step in the examination process.
Data deemed appropriate for interpretation/comparison (see 3.1 and 3.5) based on developmental validation studies, the laboratory’s internal validation studies, and the laboratory’s documented and verified interpretation and comparison protocol.
A reinforced modified sulfur material, available in flake form that is a safer, stronger alternative to using pure sulfur in casting snow impressions.
a peak resulting from the simultaneous detection of two photons; this is manifested as a peak at the combined energy of line(s) for the specific element(s) involved.
a spectral artifact that results from the simultaneous detection of two X-rays, manifested as a peak at the combined energy of the detected X-rays.
use of a registered overlay as an aid to comparison.
A report used to document additional work performed with subsequent reporting of results
Attestation by the product supplier that a product supplied is in conformity with specified requirements.
the sum of all the work done to extinguish a fire, beginning at the time of its discovery.
The placement of human remains on the surface of the ground.
a colorant bound to the surface of a fiber.
Profile that results from the intersection of the real surface by a specified plane.
The subconscious impulse for the dog to defend itself from real or imagined danger.
The analysis of specimens from living subjects to determine the presence or absence of toxic substances.
Temporary invalidation of the statement of conformity for all or part of the specified scope of attestation.
Scientific Working Group for Disaster Victim Identification
Scientific Working Group on Friction Ridge Analysis, Study, and Technology.
Scientific Working Group for Forensic and Investigatory Voice.
to manually pass a magnetically encoded card through a card reader device to transfer information from the card.
Conformance to the relationships between fields, subfields, or information items within atransaction to other values within the same transaction as specified in this standard.
a class of manufactured polymeric fibers, which are synthesized from chemical compounds (for example, nylon and polyester).
(1) errors repeatedly introduced through automation (for example, errors in template generation or comparison); (2) errors repeatedly introduced through operational practices in an organization or unit (for example, improper lighting or camera position guidance).