1. Either of two large reptiles, Alligator mississipiensis of the southeast United States or A. sinensis of China, having sharp teeth and powerful jaws. They differ from crocodiles in having a broader, shorter snout.
2. Leather made from the hide of one of these reptiles.
3. A tool or fastener having strong, adjustable, often toothed jaws.

[Alteration of Spanish el lagarto, the lizard : el, the (from Latin ille, that) + lagarto, lizard (from Latin lacertus).]

WORD HISTORY   In The Travailes of an Englishman, published in 1568, Job Hortop says that "in this river we killed a monstrous Lagarto or Crocodile." This killing gives rise to the first recorded instance of alligator in English, obviously in a different form from the one familiar to modern speakers. Alligator, which comes to us from Spanish el lagarto, "the lizard," was modified in pronunciation and form in several ways before taking on the form alligator. Such changes, referred to by linguists as taboo deformation, are not uncommon in a name for something that is feared and include, for example, the change in sequence of the r and t that occurred between el lagarto and alligator. An interesting parallel case is crocodile, which appears in Spanish, for example, as cocodrilo, with a similar difference in the sequence of the r. The earliest recorded form of alligator that is similar to ours appears in Shakespeare's Romeo and Juliet (First Folio, 1623): "In his needie shop a tortoyrs hung,/An Allegater stuft."

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.