rattler has definitions from the fields of zoology,transportation
1
[ noun ] (zoology) pit viper with horny segments at the end of the tail that rattle when shaken

Synonyms

rattlesnake

Used in print

(Clifford H. Pope, The Giant Snakes....)

Oliver , in his summary of the habits of the snakes of the United_States , could supply data on the maturing period for only three species in_addition_to the rattlers , which I shall consider separately .

2
[ noun ] Last name, frequency rank in the U.S. is 21302
3
[ noun ] (transportation) a railroad train consisting of freight cars

Synonyms

freight_train

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