Yes, EQUATOR is a Scrabble word!

Letter values in Scrabble US: E 1, Q 10, U 1, A 1, T 1, O 1, R 1.

Is it a valid word?

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

an imaginary line around the Earth forming the great circle that is equidistant from the north and south poles
a circle dividing a sphere or other surface into two usually equal and symmetrical parts