Yes, RESOLUTION is a Scrabble word!

Letter values in Scrabble US: R 1, E 1, S 1, O 1, L 1, U 1, T 1, I 1, O 1, N 1.

Is it a valid word?

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

a formal expression by a meeting; agreed to by a vote
the ability of a microscope or telescope to measure the angular separation of images that are close together
the trait of being resolute
finding a solution to a problem
something settled or resolved; the outcome of decision making
analysis into clear-cut components
(computer science) the number of pixels per square inch on a computer-generated display; the greater the resolution, the better the picture
the subsidence of swelling or other signs of inflammation (especially in a lung)
(music) a dissonant chord is followed by a consonant chord
a statement that solves a problem or explains how to solve the problem
a decision to do something or to behave in a certain manner

Also: resolving power, firmness of purpose.