specification vs spec

specification and spec both are nouns.

Word	Noun	Adjective	Verb	Adverb
specification	Yes	No	No	No
spec	Yes	No	No	No

As nouns, specification and spec are synonyms defined as:

specification and spec: a detailed description of design criteria for a piece of work

specification (noun)	spec (noun)
a restriction that is insisted upon as a condition for an agreement	a detailed description of design criteria for a piece of work
a detailed description of design criteria for a piece of work
naming explicitly
(patent law) a document drawn up by the applicant for a patent of invention that provides an explicit and detailed description of the nature and use of an invention