Yes, PROSPECTUSES is a Scrabble word!

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

Is it a valid word?

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

a formal written offer to sell securities (filed with the SEC) that sets forth a plan for a (proposed) business enterprise
a catalog listing the courses offered by a college or university

Also: course catalog, course catalogue.