In engineering and manufacturing, the term specification has the following meanings:
Technical requirement
An essential technical requirement for items, materials, or services, including the procedures to be used to determine whether the requirement has been met. Specifications may also include requirements for preservation, packaging, packing, and marking. See requirements analysis.
Procurement
An official document intended primarily for supporting procurement, which document clearly and accurately describes the essential technical requirements for items, materials, or services, including the procedures by which it will be determined that the requirements have been met.
An example of a Federal specification is FIPS-PUB 159, Detail Specification for 62.5-μm Core Diameter /125-μm Cladding Diameter Class Ia Multimode Optical Fibers.
Source: from Federal Standard 1037C and from MIL-STD-188
See also: Program specification
