YAY

from WordNet (r) 3.0 (2006)

Yay
    n 1: a branch of the Tai languages

from The Free On-line Dictionary of Computing (8 July 2008)

Yet Another Yacc
Yay

   <tool> (Yay) An extension of {Yacc} with {LALR2} parsing.

   Yay is available from {Bull} as part of the {University of
   Waterloo Tools} package maintained by <[email protected]>.

   (1994-11-09)

from V.E.R.A. -- Virtual Entity of Relevant Acronyms (June 2006)

YAY
       Yet Another YACC (YACC, Bull)