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.
chemical, analyses in which the amount or concentration of an analyte may be determined (estimated) and expressed as a numerical value in appropriate units.
Discussion—Qualitative analysis may take place without quantitative analysis, but quantitative analysis requires the identification (qualification) of the analytes for which numerical estimates are given.
any process used to extract measurable data from an image.
An assay designed to measure the concentration of an analyte within a sample
A means for quantifying the amount of nucleic acid present in a sample using PCR.
Property of a phenomenon, body, or substance, where the property has a magnitude that can be expressed as a number and a reference.
Number and reference together expressing magnitude of a quantity.
A systematic search of an area in a series of point-to-point patterns utilizing the wind to the canine's best advantage.
(n) The nucleotide or protein sequence that has an unknown source (i.e., evidence sequence), or (v) the action of searching an unknown sequence against a database.
The percent of the query sequence length that is included in the aligned segment with a hit.
question of whether two or more items have the same origin or have different origins, or who or what the origin of an item is
associated with the matter under investigation about which there is some question, including, but not limited to, whether the questioned and known items have a common origin.
in image analysis and facial identification, an image of an individual or object whose identity is unknown or in question and has been recorded electronically or by other medium. (Compare known image.)
An item of unknown source (impression or otherwise) that is normally recovered from a crime scene.
An impression or image of friction ridge skin whose source or identity is unknown; it can include latent impressions, impressions from an unknown source or a known source.
An impression or image of friction ridge skin whose source or identity is unknown; it can include latent impressions, impressions from an unknown source or a known source.
An impression or image of friction ridge skin whose source or identity is unknown; it can include latent impressions, impressions from an unknown source or a known source.
geological evidence of unknown origin, or a questioned sample, typically consists of debris adhering to an evidentiary object (for example, tire, wheel well, garment, shoe, digging tool); exogenous soil left at a crime scene (transferred from a shoe/tire, or adhering to a re-buried body/object); or debris recovered from within a body (nasal, stomach, or lung contents).
material collected as or from items of evidence which have a known location but an unknown originating source.
Discussion—Soil evidence of unknown origin, or questioned soil sample, typically consists of: debris adhering to an evidentiary object or exhibit (for example, tire, wheel well, garment, shoe, digging tool); foreign soil left at a crime scene (for example, transferred from a shoe/tire, or adhering to a re-buried body/object); or debris recovered from on or within a body (for example, nasal, stomach, or lung contents).
a coating sample whose original source is unknown.
soil evidence of unknown origin, or questioned soil sample, typically consists of: debris adhering to an evidentiary object or exhibit (for example, tire, wheel well, garment, shoe, digging tool); exogenous soil left at a crime scene (for example, transferred from a shoe/tire, or adhering to a re-buried body/object); or debris recovered from within a body (for example, nasal, stomach, or lung contents).
A voice signal from an individual who is unknown and has not yet been linked to anypreviously encountered individual. Note: The task of speaker identification is to link aquestioned voice signal to a known voice signal through determination of a commonspeaker.
A multimedia framework developed by Apple, Inc. It allows the use of many differentcodec formats. The native file format for QuickTime video specifies a multimediacontainer file that contains one or more tracks. Each track either contains a digitallyencoded media stream using a specific format or a data reference to the media streamlocated in another file.
Electromagnetic transmission of heat energy; increases the sensible temperature of any substance capable of absorbing the radiation, especially solid and opaque objects.
Heat transfer by way of electromagnetic waves that are longer than visible light waves and shorter than radio waves.
An image produced on a sensitive plate or film by X-rays or similar radiation, and typically used in medical examination.
An image produced on a sensitive plate or film by x-rays or similar radiation, and typically used in medical examination range of motion.
a type of temporary data storage (memory) that can be read and changed while the computer is in use.
Discussion—Data stored in random-access memory is lost if the system loses power.
When the choice of something or the placement of something is random the source placed is equally likely to be either location.
A feature or defect specific to one stamp that can occur in the manufacturing process or from individual usage occurring after manufacture (for example, wear and damage defects such as cuts and gouges, reproducible blemishes, impression voids, improper and extraneous inking, or coincidental peripheral printing). The position, orientation, size and shape of these characteristics are essential to the identification of a stamp as the source of an impression.
The subconscious impulse on the part of the canine to rise in status within the pack social order
A Category 0 scoring function. See 4.2.4. A rank-score only scoring function is either non-quantified, inconsistent, or non-explainable.
the pattern scanned by the electron beam on a sample; the raster dimensions change inversely with magnification.
See heat release Rate (HRR).
in image analysis, a digital camera or scanner file format, usually proprietary, for minimally processed digital image data.
Ordinate values that come directly from the instrument which have not been manipulated (e.g.,trimmed, filtered, and/or interpolation applied).
A family of file formats, often specific to different models of digital imageryequipment, that are not yet processed for storage in a 'printable' image format such asJPEG or TIFF. The file extension '.raw' is only one such format.
thin oblong crystals with length about twice the width, resembling a safety razor blade.
Royal Canadian Mounted Police.
a type of permanent data storage (memory) that can be read but not altered by the system.
Discussion—Data stored in read-only memory is not affected by power loss to the system.
A chemical used to react with another chemical, often to confirm or deny the presence of the second chemical.
a chemical used to react with another chemical, often to confirm or deny the presene of the second chemical.
A sample that contains no analyte, but contains the buffer, test reagents, or other materials required to perform a particular test. This is a negative control where results are not expected. The observation where the result(s) in this control may indicate the presence of contaminated or compromised reagents, which may impact the DNA or the serological results observed from samples tested at the same time. For forensic DNA testing this control is treated the same as, and parallel to, the DNA samples being analyzed.
A verbal command given to the canine, terminating with the canine returning to the canine handler. The canine's response to return to the canine handler on command.
The recall rate is also known as true positive rate. It is defined as the number (or percentage) of toolmark specimens containing a Known-Match in the test set for which a Known-Match is correctly determined.
The document or other substrate that received indentations, other paper fiber disturbances, or other markings.
process of deciding whether items have potential forensic value
Note 1 to entry: Enhancement can aid recognition