pineapple

from WordNet (r) 3.0 (2006)

pineapple
    n 1: a tropical American plant bearing a large fleshy edible
         fruit with a terminal tuft of stiff leaves; widely
         cultivated in the tropics [syn: {pineapple}, {pineapple
         plant}, {Ananas comosus}]
    2: large sweet fleshy tropical fruit with a terminal tuft of
       stiff leaves; widely cultivated [syn: {pineapple}, {ananas}]

from The Collaborative International Dictionary of English v.0.48

fragmentation grenade \fragmentation grenade\ n. (Mil.)
   A type of hand grenade designed to burst into multiple
   fragments upon detonation of the explosive charge; the
   fragments fly away at high velocity, killing or wounding
   persons nearby. Contrasted to {concussion grenade}. The
   common type of fragmentation grenade used by the American
   military was sometimes jocosely referred to as a {pineapple}
   from its reticulated surface appearance, resembling that of
   the fruit.
   [PJC]

from The Collaborative International Dictionary of English v.0.48

Pineapple \Pine"ap`ple\, n. (Bot.)
   A tropical plant ({Ananassa sativa}); also, its fruit; -- so
   called from the resemblance of the latter, in shape and
   external appearance, to the cone of the pine tree. Its origin
   is unknown, though conjectured to be American.
   [1913 Webster]