squeaker

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

• noun One that squeaks.
• noun Informal Something, such as an election, that is won, passed, or achieved by the narrowest of margins or at the very last moment.

from The Century Dictionary.

• noun A European water-beetle, Pelobius tardus, which is a very loud stridulator. They are sold as curiosities in the London markets.
• noun Any stridulating crab, as the American lady-crab.
• noun One who or that which squeaks.
• noun A young bird, as a pigeon, partridge, or quail; a chirper; a peeper; a squealer.
• noun An Australian crow-shrike of the genus Strepera, as S. cuneicauda (oftener called anaphonensis, after Temminck, 1824, a specific name antedated by the one given by Vieillot in 1816), mostly of a grayish color, 19 inches long: so called from its cries.
• noun One who confesses, or turns informer.

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

• noun One who, or that which, squeaks.
• noun (Zoöl.) The Australian gray crow shrike (Strepera anaphonesis); -- so called from its note.
• noun colloq., colloq. A contest won by a small margin.
• noun colloq. A narrow escape from harm.

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

• noun One who or that which squeaks.
• noun A party toy that uncoils with a squeaking sound when blown
• noun slang An informer
• noun US A game or election won by a narrow margin
• noun The Australian gray crow shrike (Strepera anaphonesis).

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

• noun something achieved (or escaped) by a narrow margin
• noun any artifact that makes a squeaking sound when used