Yes, RELEASE is a Scrabble word!

Letter values in Scrabble US: R 1, E 1, L 1, E 1, A 1, S 1, E 1.

Is it a valid word?

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

merchandise issued for sale or public showing (especially a record or film)
the act of liberating someone or something
a process that liberates or discharges something
an announcement distributed to members of the press in order to supplement or replace an oral presentation
the termination of someone's employment (leaving them free to depart)
euphemistic expressions for death
a legal document evidencing the discharge of a debt or obligation
a device that when pressed will release part of a mechanism
activity that frees or expresses creative energy or emotion
the act of allowing a fluid to escape
a formal written statement of relinquishment
(music) the act or manner of terminating a musical phrase or tone

release, as from one's grip
grant freedom to; free from confinement
let (something) fall or spill from a container
prepare and issue for public distribution or sale
eliminate (a substance)
generate and separate from cells or bodily fluids
make (information) available for publication
part with a possession or right
release (gas or energy) as a result of a chemical reaction or physical decomposition
make (assets) available

Also: press release, tone ending, let go of, let go, bring out, put out, give up.