Yes, TERMINALS is a Scrabble word!

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

Is it a valid word?

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

station where transport vehicles load or unload passengers or goods
a contact on an electrical device (such as a battery) at which electric current enters or leaves
either extremity of something that has length
electronic equipment consisting of a device providing access to a computer; has a keyboard and display