olemus
süsteemi- ja tarkvaratehnikas:
nõuete spetsifikatsiooni osa või eraldi dokument,
määrab funktsioonid,
mida süsteem või komponent peab täitma
=
a description of the product to be supplied in terms of the functions it will perform and facilities required to meet the user requirements

ülevaateid
http://www.its-all-design.com/what-actually-goes-in-a-functional-specification/

http://www.bridging-the-gap.com/functional-specification/

https://en.wikipedia.org/wiki/Functional_specification

http://www.ofnisystems.com/services/validation/functional-requirements/

https://www.altexsoft.com/blog/business/functional-and-non-functional-requirements-specification-and-types/

https://theappsolutions.com/blog/development/functional-vs-non-functional-requirements/