Yes, ELIMINATION is a Scrabble word!

Letter values in Scrabble US: E 1, L 1, I 1, M 3, I 1, N 1, A 1, T 1, I 1, O 1, N 1.

Is it a valid word?

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

the act of removing or getting rid of something
the bodily process of discharging waste matter
analysis of a problem into alternative possibilities followed by the systematic rejection of unacceptable alternatives
the act of removing an unknown mathematical quantity by combining equations
the murder of a competitor

Also: reasoning by elimination.