pineapple

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A tropical American plant (Ananas comosus) having large swordlike leaves and a large, fleshy, edible, multiple fruit with a terminal tuft of leaves.
• noun The fruit of this plant.
• noun Slang A hand grenade.

from The Century Dictionary.

• noun The cone or strobilus of the pine; a pine-cone.
• noun The fruit of Ananas (Ananassa) sativa: so called from its resemblance to a pine-cone.
• noun The plant Ananas sativa, a native of tropical South America, now widely cultivated and naturalized throughout the tropics.
• noun A fish of the family Diodontidæ, a kind of porcupine-fish, Chilomycterus geometricus: so called from the prickly skin and the shape when inflated.

from the GNU version of the Collaborative International Dictionary of English.

• noun (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.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A tropical plant, Ananas comosus, native to South America, having thirty or more long, spined and pointed leaves surrounding a thick stem.
• noun The ovoid fruit of the pineapple plant, which has very sweet white or yellow flesh, a tough, spiky shell and a tough, fibrous core.
• noun slang A hand grenade.
• noun slang An Australian fifty dollar note.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a tropical American plant bearing a large fleshy edible fruit with a terminal tuft of stiff leaves; widely cultivated in the tropics
• noun large sweet fleshy tropical fruit with a terminal tuft of stiff leaves; widely cultivated