Source : Webster's Revised Unabridged Dictionary (1913)

Stew \Stew\, v. t. [imp. & p. p. {Stewed}; p. pr. & vb. n.
   {Stewing}.] [OE. stuven, OF. estuver, F. ['e]tuver, fr. OF.
   estuve, F. ['e]tuve, a sweating house, a room heated for a
   bath; probably of Teutonic origin, and akin to E. stove. See
   {Stove}, and cf. {Stive} to stew.]
   To boil slowly, or with the simmering or moderate heat; to
   seethe; to cook in a little liquid, over a gentle fire,
   without boiling; as, to stew meat; to stew oysters; to stew
   apples.

Source : WordNet®

stewing
     n 1: an extreme state of worry and agitation; "his stewing over
          the fight kept him awake most of the night"
     2: cooking in a boiling liquid [syn: {boiling}, {simmering}]