Yes, PROCESSES is a Scrabble word!

Letter values in Scrabble US: P 3, R 1, O 1, C 3, E 1, S 1, S 1, E 1, S 1.

Is it a valid word?

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

a particular course of action intended to achieve a result
(psychology) the performance of some composite cognitive activity; an operation that affects mental contents
a writ issued by authority of law; usually compels the defendant's attendance in a civil suit; failure to appear results in a default judgment against the defendant
a mental process that you are not directly aware of
a natural prolongation or projection from a part of an organism either animal or plant
a sustained phenomenon or one marked by gradual changes through a series of states

subject to a process or treatment, with the aim of readying for some purpose, improving, or remedying a condition
deal with in a routine way
perform mathematical and logical operations on (data) according to programmed instructions in order to obtain the required information
institute legal proceedings against; file a suit against
march in a procession
shape, form, or improve a material
deliver a warrant or summons to someone

Also: cognitive process, mental process, cognitive operation, unconscious process, physical process, work on, swear out.