1. An essential technical requirement for items, materials, or services, including the procedures to be used to determine whether the requirement has been met. Note: Specifications may also include requirements for preservation, packaging, packing, and marking.
2. 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.
A specification is typically a company specific document which sets parameters for an item. An example of a specification would be geometric (dimensional), electrical, performance, appearance and/or other requirement parameters for a specific device a specific manufacturer makes.
However, a company (or other entity such as a government) may develop a specification for something such as a device or part which will be purchased. Thus, a specification may be developed for many companies as a requirement by one company (or a few companies) which is applicable to a device or part produced by any company accepting a contract.