The Collaborative International Dictionary of English v.0.48:

Mast \Mast\, v. t. [imp. & p. p. Masted; p. pr. & vb. n.
   Masting.]
   To furnish with a mast or masts; to put the masts of in
   position; as, to mast a ship.
   [1913 Webster] Mastaba

The Collaborative International Dictionary of English v.0.48:

Masted \Mast"ed\, a.
   Furnished with a mast or masts; -- chiefly in composition;
   as, a three-masted schooner.
   [1913 Webster]

WordNet (r) 3.0 (2006):

masted
    adj 1: having or furnished with a mast; often used in
           combination; "probably was so masted when she set forth"-
           S.E.Morrison; "a three-masted bark"