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 body of facts, information, or material objects indicating whether a theory or proposition is true or valid.
A body of facts, information, or material objects indicating whether a belief or proposition is true or valid.
A body of facts, information, or material objects indicating whether a belief or proposition is true or valid.
The process of a canine locating and indicating items that contain a trained human scent. This may be non-targeted or targeted based on the discipline.
The process of a canine locating and indicating items that contain a trained odor/human scent. This may be non-specific or targeted based on the discipline. (See article search.)
A canine trained to locate and indicate items in question by means of detecting a trained odor/ human scent.
Data derived from biological specimens of unknown source.
In facial identification, an individual whose role it is to perform a facial examination
In facial identification, an individual whose role it is to perform a facial examination.
An individual authorized to conduct independent friction ridge examinations for the forensic service provider by observing and interpreting data, making decisions, forming conclusions and opinions, issuing reports and/or providing testimony. Use of the term “examiner” in these documents refers to a “competent friction ridge examiner” and not a “trainee.”
A photograph that contains sufficient quality of information for the purpose of conducting aforensic footwear and tire examination.
Although NIEM contains thousands of elements it does not contain everything needed inan XML exchange. It contains the most common building blocks. In addition,implementers can define, in other exchange schemas, user-defined elements from theimplementers domain.
A filter used in fluorescence microscopy that transmits specific bands or wavelengths of energy capable of inducing visible fluorescence in various substrates
a filter used in fluorescence microscopy that transmits specific bands or wavelengths of energy capable of inducing visible fluorescence in various substrates.
A result that compared items did not originate from the same source, are not the same substance, or do not share the same composition or classification, based on an exclusionary difference.
Also referenced in ASB 097, Terminology Used for Forensic Footwear and Tire Evidence.
The result of a comparison between two hair samples in which exclusionary differences are observed in the characteristics of the questioned hair that are not present in the known hair sample, and therefore the donor of the known sample can be excluded as a possible source of the questioned hair. DiscussionThis result is reached in a compara tive hair examination when exclusionary differences (for example, color, characteristics indicative of ancestry) are noted in the macroscopic or microscopic characteristics between the questioned and known hairs. In these circumstances, the source of the known hairs, as represented by the known sample, is eliminated as a possible source of the questioned hair.
the result of a comparison between two hair samples in which exclusionary differences are observed in the characteristics of the questioned hair that are not present in the known hair sample, and therefore the donor of the known sample can be excluded as a possible source of the questioned hair.
Discussion—This result is reached in a compara- tive hair examination when exclusionary differences (for example, color, characteristics indicative of ancestry) are noted in the macroscopic or microscopic characteristics between the questioned and known hairs. In these circumstances, the source of the known hairs, as represented by the known sample, is eliminated as a possible source of the questioned hair.
The result of a comparison between two hair samples in which the characteristics of the questioned hair differ from those present in the known hair sample, and therefore the donor of the known sample cannot be included as a possible source of the questioned hair. DiscussionThis result is reached in a compara- tive hair examination when differences are noted in the macroscopic or microscopic characteristics between the ques- tioned and known hairs; however, the differences are insufficient for an absolute exclusion of a person as a possible source. This could be due to the natural variation that occurs in hairs as a biological specimen, the effect that time or environment can have upon a hair, or the reference sample does not capture the complete variation of the individual's hair.
the result of a comparison between two hair samples in which the characteristics of the questioned hair differ from those present in the known hair sample, and therefore the donor of the known sample cannot be included as a possible source of the questioned hair.
Discussion—This result is reached in a comparative hair examination when differences are noted in the macroscopic or microscopic characteristics between the questioned and known hairs; however, the differences are insufficient for an absolute exclusion of a person as a possible source. This could be due to the natural variation that occurs in hairs as a biological specimen, the effect that time or environment can have upon a hair, or the reference sample does not capture the complete variation of the individual’s hair.
A type of location search in which a scent match is not indicated by the canine thereby excluding an individual as the scent contributor.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
Discussion—What is sufficient depends on the performance and limitations of the method used on the material in question.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
a difference in a feature or property between compared items that is substantial enough to determine that they did not originate from the same source.
Evidence that may be favorable to the accused, impeach the prosecution’s evidence, or mitigate the offense.
A specimen of physical evidence of known origin
The friction ridge prints of an individual, associated with a known or claimed identity,and deliberately recorded electronically, by ink, or by another medium (also called 'known prints').
Quantity defining an interval about a result of a measurement that may be expected to encompass a large fraction of the distribution of values that could reasonably be attributed to the measurand
Quantity defining an interval about a result of a measurement that may be expected to encompass a large fraction of the distribution of values that could reasonably be attributed to the measurand. DISCUSSION(1) The fraction may be regarded as the coverage probability or level of confidence of the interval. (2) To associate a specific level of confidence with the interval defined by the expanded uncertainty requires explicit or implicit assumptions regarding the probability distribution characterized by the measurement result and its combined standard uncertainty. The level of confidence that may be attributed to this interval can be known only to the extent to which such assumptions can be justified. (3) An expanded uncertainty U is calculated from a combined standard uncertainty uc and coverage factor k using: U =k X uc.
The number of distinct alignments expected by chance; the default sorting metric in BLAST search results.
Anyone testing any idea has a strong expectation that leads to an influence about the outcome.
A person displaying special skill and knowledge in a given area derived from training, education, or experience.
The testimony made by a qualified person about a scientific, technical, or professional issue. An expert is often called upon to testify due to his/her familiarity with the subject or special training in the field.
A coherent, scientifically sound statement or statements regarding the meaning of analytical findings in a forensic case that is formulated from a consideration of the synthesis of analytical data, pre-analytical factors, case history, and other relevant information
A material with a pressure ratio (maximum pressure/pressure at ignition, in absolute units) equal to or greater than 2.0 in any test when tested using the explosibility or Go/No-Go screening test described in Section 13 of ASTM E1226, Standard Test Method for Explosibility of Dust Clouds. [68, 2018]
The sudden conversion of potential energy (chemical or mechanical) into kinetic energy with the production and release of gases under pressure, or the release of gas under pressure. These high-pressure gases then do mechanical work such as moving, changing, or shattering nearby materials.
the sudden conversion of potential energy (chemical or mechanical) into kinetic energy with the production and release of gases under pressure, or the release of gas under pressure; these high-pressure gases then do mechanical work such as moving, changing, or shattering nearby materials.
A single substance, or a mixture of substances, that is capable of producing an explosion upon initiation (see high explosives and low explosives). explosive compound, na single chemical compound that can produce an explosion. explosive mixture, na mixture of separate fuel and oxidizer components that together can produce an explosion.