Yes, RECEIVER is a Scrabble word!

Letter values in Scrabble US: R 1, E 1, C 3, E 1, I 1, V 4, E 1, R 1.

Is it a valid word?

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

set that receives radio or tv signals
(law) a person (usually appointed by a court of law) who liquidates assets or preserves them for the benefit of affected parties
earphone that converts electrical signals into sounds
a person who receives something
the tennis player who receives the serve
a football player who catches (or is supposed to catch) a forward pass

Also: receiving system, telephone receiver, pass receiver, pass catcher.