Yes, DOMINO is a Scrabble word!

Letter values in Scrabble US: D 2, O 1, M 3, I 1, N 1, O 1.

Is it a valid word?

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

United States rhythm and blues pianist and singer and composer (born in 1928)
a loose hooded cloak worn with a half mask as part of a masquerade costume
a mask covering the upper part of the face but with holes for the eyes
a small rectangular block used in playing the game of dominoes; the face of each block has two equal areas that can bear 0 to 6 dots

Also: fats domino, antoine domino, half mask, eye mask.