Yes, ABSORPTION is a Scrabble word!

Letter values in Scrabble US: A 1, B 3, S 1, O 1, R 1, P 3, T 1, I 1, O 1, N 1.

Is it a valid word?

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

(chemistry) a process in which one substance permeates another; a fluid permeates or is dissolved by a liquid or solid
(physics) the process in which incident radiated energy is retained without reflection or transmission on passing through a medium
the social process of absorbing one cultural group into harmony with another
the process of absorbing nutrients into the body after digestion
complete attention; intense mental effort
the mental state of being preoccupied by something

Also: soaking up.