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 friction ridge image containing friction ridge detail produced on a surface by pressure.
Image formed by pressure.
Manner in which the paper is embossed or shredded.
A phenomenon by which an animal during a formative stage of life forms a lasting attachment to, and preference for, some object or activity through exposure to the same independent of consequences. Operational usage: A method of initial odor/scent discrimination training.
any combination of items or components that are neither originally designed nor produced to be used in conjunction with each other and, when placed together, constitute a mechanism that has the capability of exploding and causing personal injuries and property damage.
Reinforcement delivered despite the appropriateness of any response on the part of the subject.
chemical compound, metal, or mixture capable of producing intense heat.
chemical compound, metal, or mixture capable of producing intense heat.
a device or mechanism used to initiate an incendiary fire.
A fire that is intentionally ignited in an area or under circumstances where and when there should not be a fire.
A management system designed to enable effective and efficient domestic incident management by integrating a combination of facilities, equipment, personnel, procedures and communications operating within a common organizational structure.
A soil level in an excavation or grave that does not contain evidence or data relevant to the scene under investigation. It does not mean that it is culturally or archaeologically sterile (e. g. historic or prehistoric artifacts or features may be present but are not related to the event under investigation).
A friction ridge not fully developed that may appear shorter and thinner in appearancethan fully developed friction ridges.
The InterNational Committee for Information Technology Standards
A type location check in which a scent match is indicated by the canine thereby including an individual as the scent contributor.
A conclusion for which an individual is a potential contributor of DNA (i.e., cannot be excluded) obtained from an evidentiary sample based on the comparison of DNA data; a statement of inclusion does not confirm that an individual is a source of the DNA.
spectral artifacts that result from inelastic scattering of the tube target characteristic X-rays by the sample.
Discussion—Because energy is lost in inelastic scattering, incoherent scatter peaks occur at a lower energy than the tube target characteristic X-rays.
the result of a comparison between two hair samples in which similarities and differences were observed in the characteristics of the provided standard and the questioned hair to the extent that the known source of the standard could not be included or excluded as a possible source of the questioned hair.
the result of a comparison between two hair samples in which similarities and differences were observed in the characteristics of the provided standard and the questioned hair to the extent that the known source of the standard could not be included or excluded as a possible source of the questioned hair.
A determination that no conclusion (i.e., inclusion or exclusion) can be drawn from the comparison of reference data to evidentiary data. This could also result from statistical analyses that fail to provide sufficient support for an inclusion or exclusion.
The conclusion that the observed data does not provide more support for one proposition over the other.
Results that do not meet criteria for reporting, or were unsuitable due to analytical interferences or condition of the sample
The conclusion that the observed data provide more support for the proposition that the impressions originated from different sources rather than the same source; however, there is insufficient support for a Source Exclusion.
The conclusion that the observed data provide more support for the proposition that the impressions originated from the same source rather than different sources; however, there is insufficient support for a Source Identification.
in fire debris, used as a generic term for substituted forms of indan, a compound which consists of a benzene ring fused to a cyclopentane ring.
Discussion—In the plural form, sometimes used in fire debris analysis to refer to the class of compounds based on indan; they can be found in gasoline and, to an extent, in other petroleum products.
Latent or visible impressions and/or embossments in paper or other media. This also includes paper fiber disturbances which do not optically appear as impressions.
Latent or visible impressions in paper or other media.
Scientific usage: Statistical studies assume a property called independence - a situation where the data collected are not related to each other because they come from a random sample from the population examined; independence is often assumed but seldom tested. Good statistical testing tests for independence when its presence is unclear. Operational usage: The canine's capability to perform without assistance or being influenced by the canine handler.
Scientific usage: Statistical studies assume a property called independence - a situation where the data collected are not related to each other because they come from a random sample from the population examined; independence is often assumed but seldom tested. Good statistical testing tests for independence when its presence is unclear. Operational usage: The canine's capability to perform without assistance or being influenced by the canine handler.
In the simplest experiment this is the item that you vary or that varies as a function of the way the experiment is designed.
The process of obtaining a second analysis from a forensic dental age assessment practitioner, blinded to the results of the first practitioner's assessment.
The canine's response to the odor/scent in the manner in which it has been trained, independently and without distraction. (See alert, final response.)
the attribute(s) that establish(es) a single source.
Discussion—Other terms used include random accidental characteristics, randomly acquired characteristics, and distinguishing characteristics.
A decision which identifies an organism as the source of the DNA that produced an evidentiary single-source or major contributor profile; This statement is often based on population frequency estimates that are more rare than some defined number.
Specially designed portion of a checkwriter impression immediately preceding that of the collective segments or the machine part from which the designed impression is created.
a term indicating an individual can be discriminated to the exclusion of all other sources.
Discussion—Hairs cannot be individualized via microscopical hair comparison.
a term indicating an individual can be discriminated to the exclusion of all other sources.
Discussion—Hairs cannot be individualized by means of microscopical hair comparison.
The process by which a person starts from a particular experience and proceeds to generalizations. The process by which hypotheses are developed based upon observable or known facts and the training, experience, knowledge, and expertise of the observer.
The analysis of specimens from children or their caregivers in cases of suspected exposure to harmful substances.
The interval in human dental development that begins at birth, includes the presence of the developing, developed and resorbing primary dentition as well as the initial development of the permanent dentition. This interval includes the early period of mixed primary and permanent dentitions and ends when the last primary tooth is exfoliated normally. Note 1 to entry: During the adolescent age and adult dental age intervals, primary teeth may be atypically retained for various reasons, including congenital absence or ectopic eruption of the permanent teeth that would typically replace them.
Referring to radiant flux having wavelengths longer than the wavelengths of visible light, usually from ~700 nm to 1400 nm (~0.7 μm to 1.4 μm) as per the International Commission on Illumination (CIE) for IR-A.
The emission of radiant energy during a transition from an excited electronic state of an atom, molecule, or ion to a lower electronic state (fluorescence or phosphorescence, or both), where the spectrum of the excitation source is in the ultraviolet (UV) or visible region of the electromagnetic spectrum, or both, and the spectrum of the emitted energy is in the far red or infrared (IR) region of the electromagnetic spectrum.
As related to the polymerase chain reaction (PCR), any substance that interferes with or prevents the synthesis of DNA during the amplification process.
The fundamental training associated with detector canine training which consists of, but not limited to: bonding/relationship building, obedience, basic odor/scent discrimination, and basic search techniques.
The fundamental training associated with detector canine training which consists of, but not limited to: bonding/relationship building, obedience, basic odor/scent discrimination, and basic search techniques.
The fundamental training associated with detector canine training which consists of, but not limited to: bonding/relationship building, obedience, basic odor/scent discrimination, and basic search techniques.
The fundamental training associated with detector canine training which consists of, but not limited to: bonding/relationship building, obedience, basic scent discrimination, and basic search techniques.
The fundamental training associated with detector canine training which consists of, but not limited to: bonding/relationship building, obedience, basic scent discrimination, and basic search techniques.
The fundamental training associated with detector canine training which consists of, but not limited to: bonding/relationship building, obedience, basic scent discrimination, and basic search techniques.