Yes, RENAISSANCES is a Scrabble word!

Letter values in Scrabble US: R 1, E 1, N 1, A 1, I 1, S 1, S 1, A 1, N 1, C 3, E 1, S 1.

Is it a valid word?

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

the period of European history at the close of the Middle Ages and the rise of the modern world; a cultural rebirth from the 14th through the middle of the 17th centuries
the revival of learning and culture