Yes, SPECIFICATIONS is a Scrabble word!

Letter values in Scrabble US: S 1, P 3, E 1, C 3, I 1, F 4, I 1, C 3, A 1, T 1, I 1, O 1, N 1, S 1.

Is it a valid word?

SPECIFICATIONS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

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
a restriction that is insisted upon as a condition for an agreement