proa UK /ˈpɹəʊ.ə/US /ˈpɹoʊ.ə/ noun1 •A sailing vessel found in the waters of Micronesia and Indonesia; it has a single, large outrigger and a triangular sail.I noticed that on the sea were numerous fantastically shaped canoes—or rather boats—like Malay proas, or the canoes used by many of the South Sea islanders. — 1894 formsproas