Yes, GROUNDINGS is a Scrabble word!

Letter values in Scrabble US: G 2, R 1, O 1, U 1, N 1, D 2, I 1, N 1, G 2, S 1.

Is it a valid word?

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

fix firmly and stably
confine or restrict to the ground
place or put on the ground
instruct someone in the fundamentals of a subject
bring to the ground
hit or reach the ground
throw to the ground in order to stop play and avoid being tackled behind the line of scrimmage
hit a groundball
hit onto the ground
cover with a primer; apply a primer to
connect to a ground
use as a basis for; found on

Also: run aground.