Rattlesnake

wiktionary

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From rattle +‎ snake.

etymonline

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rattlesnake (n.)

venomous serpent of the Americas noted for the rattle at the end of its tail, 1620s, from rattle + snake (n.).

RATTLE-SNAKE COCKTAIL.*

*So called because it will either cure Rattlesnake bite, or kill Rattlesnakes, or make you see them.

[Harry Craddock, "The Savoy Cocktail Book," 1930]