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.
Sidewall
Sign of elongation
signature style
1) Text-based (all allographs legible), 2) Mixed style (two or more allographs are legible), 3) Stylized (one or no allographs are legible). (NIST HF)
Signature Wipe
significance
the weight or meaning of the evidence or results.
Discussion—This definition refers to a qualitative assessment of the evidence, unless otherwise stated as a quantitative assessment (for example, statistical significance).
significant difference
A feature that is structurally divergent between items or groups of items, is outside the observed range of variation of at least one of them, and that cannot be reasonably explained.
significant similarity
A repeated distinguishing characteristic that is structurally similar between items or groups of items and is within their observed range of variation (e.g., consistent height ratio, consistent pen lift).
similarity
An observation that two impressions share a general likeness when comparing an individual feature or detail. Not to be confused with “agreement.”
similarity
An observation that two impressions share a general likeness when comparing an individual feature or detail. Not to be confused with “correspondence.”
similarity
An observation that two impressions share a general likeness when comparing an individual feature or detail. Not to be confused with “agreement.”
similarity
A feature or characteristic observed in one item or group of items that is also observed in the same form in a comparable item or group of items.
simplistic writing
Characterized by non-complex characters or strokes. (NIST HF)
simulation
An attempt to copy or reproduce handwriting (e.g., tracing, free hand, non-spurious).
Simultaneous Capture
The acquisition of images of a single biometric modality from a subject at the same time.Sequential capture over a time scale ( < 1 second) that prevents confounding of body parts ( e.g., substituting left iris for right iris) can also be considered simultaneous capture in this context.
single element typewriter
A typewriter that generates text via interchangeable "elements" that each contain a full set of characters. (SWGDOC E04)
Single Nucleotide Polymorphism Snp
DNA sequence variations that occur when a single nucleotide (A, T, C, or G) in the genome sequence is altered; these variations may be used for distinguishing individuals, and in biological relationship and ancestry testing.
Single Split Trail/Turn
Refers to a training exercise in which two subjects walk a straight line and then split into two different directions. When the canine is presented with a scent article from one of the subjects, the canine commences to trail and match the correct person to the scent article. Despite the contamination of scent from the other person on the trail the canine is still able to discriminate between scents and identify the correct subject.
single strike film ribbon
An inked ribbon wherein the substrate is a plastic film material such as polyethylene, where each area of the ribbon is capable of producing only one image. (ASTM F221)
single strike paper ribbon
An inked ribbon wherein the substrate is paper, where each area of the ribbon is capable of producing only one image. (ASTM F221)
Single-Base
Single-Base
Single-Blind Assessment/Testing
An evaluation of the canine team's ability to complete an exercise where the evaluator knows the outcome and the handler does not.
Single/Sole-Purpose Canine
A dog trained in only one discipline.
Sinoxid
Sinus Arrhythmia
A regularly irregular heart rhythm associated with changes in breathing, normal finding in the canine.
Sipes
sister lines
Sporadic inkless or partially inkless indented lines in a writing surface that are produced by the annular rim of a ball pen during the process of writing or making other markings, and which precisely run parallel to the primary ink line laid down by the ball pen.
Site
The general physical location of the incident, including the scene and the surrounding area deemed significant to the process of the investigation and support areas.
size standard
DNA fragments of known length that are analyzed in conjunction with samples during electrophoretic or other instrumental methods.
Skeletal Crystal
skeletal material
Osseous, cartilaginous, and dental tissues.
skeletal sex
Variation in the expression of skeletal traits influenced by sexual dimorphism.
skeletal trauma
A defect to osseous, dental, and/or cartilaginous tissue as a result of external forces.
skeleton, skeletal, skeletal material
Osseous, cartilaginous, and/or dental tissues.
skeleton/skeletal
Osseous, cartilaginous, and/or dental tissues.
Skeletonized Image
A representation of a friction skin image in which all pixels are white except for a 1-pixel-wide thinned black skeleton following the midpoint of each ridge. Also known as aridge tracing.
skill
How well an individual is able to produce and repeat the formation of handwritten characters. (NIST HF)
Skimmer
Skimming
skull-photo superimposition
A technique involving the superimposition of a facial photograph or video of a known individual with an unidentified skull.
skull-photo superimposition
A technique involving the superimposition of a facial photograph or video of a known individual with an unidentified skull.
Slam Fire
The accidental discharge of a firearm upon closing of the action.
slant slope
The angle or inclination of the axis of letters relative to the baseline. (NIST HF)
Slap Image
Slap fingerprints (slaps) are taken by simultaneously pressing the fingers of one hand(i.e., without the thumb) onto a scanner or fingerprint card. Slaps are also known as fourfinger simultaneous plain impressions (although if the person has more than four fingerson a hand, all of the fingers may be included in the slap image).
slit glass
Alternate scanning surface found in some digital photocopiers used in conjunction with an automatic document feeder. (SWGDOC E06)