The Collaborative International Dictionary of English v.0.48:

Proa \Pro"a\, n. [Malay pr[=a]?, pr[=a]h?.] (Naut.)
   A sailing canoe of the Ladrone Islands and Malay Archipelago,
   having its lee side flat and its weather side like that of an
   ordinary boat. The ends are alike. The canoe is long and
   narrow, and is kept from overturning by a cigar-shaped log
   attached to a frame extending several feet to windward. It
   has been called the flying proa, and is the swiftest
   sailing craft known.
   [1913 Webster]