This has two common meanings in technology:
(a) it is usually used to refer to the part of a patent in which the invention and how to practice it is described in detail, although technically it also usually includes the claims;
(b) a statement of criteria that an intended product, project or process must achieve. Specifications are prospective and in principle aspirational and may be highly detailed, laying down key requirements for the product, process or project to be successful, including operating successfully in the intended environment. All technology contracts usually include a specification.