The Collaborative International Dictionary of English v.0.48:

Lancegay \Lance"gay`\, Lancegaye \Lance"gaye`\, n. [OF.
   lancegaie, corrupted from the same source as E. assagai,
   under the influence of F. lance lance. See Assagai.]
   A kind of spear anciently used. Its use was prohibited by a
   statute of Richard II. --Nares.
   [1913 Webster]

         In his hand a launcegay,
         A long sword by his side.                --Chaucer.
   [1913 Webster]