Source : Webster's Revised Unabridged Dictionary (1913)

Decacerata \De*cac`e*ra"ta\, n. pl. [NL., fr. Gr. de`ka ten +
   ke`ras a horn.] (Zo["o]l.)
   The division of Cephalopoda which includes the squids,
   cuttlefishes, and others having ten arms or tentacles; --
   called also {Decapoda}. [Written also {Decacera}.] See
   {Dibranchiata}.

Decapoda \De*cap"o*da\, n. pl. [NL., fr. Gr. ? ten + ?, ?,
   foot.]
   1. (Zo["o]l.) The order of Crustacea which includes the
      shrimps, lobsters, crabs, etc.

   Note: They have a carapace, covering and uniting the somites
         of the head and thorax and inclosing a gill chamber on
         each side, and usually have five (rarely six) pairs of
         legs. They are divided into two principal groups:
         Brachyura and Macrura. Some writers recognize a third
         (Anomura) intermediate between the others.

   2. (Zo["o]l.) A division of the dibranchiate cephalopods
      including the cuttlefishes and squids. See {Decacera}.

Podophthalmia \Pod`oph*thal"mi*a\, n. pl. [NL. See
   {Podophthalmic}.] (Zo["o]l.)
   The stalk-eyed Crustacea, -- an order of Crustacea having the
   eyes supported on movable stalks. It includes the crabs,
   lobsters, and prawns. Called also {Podophthalmata}, and
   {Decapoda}.

Source : WordNet®

Decapoda
     n 1: lobsters; crayfish; crabs; shrimps; prawns [syn: {order
          Decapoda}]
     2: squids and cuttlefishes [syn: {order Decapoda}]