rattler vs rattlesnake

rattler and rattlesnake both are nouns.

Word	Noun	Adjective	Verb	Adverb
rattler	Yes	No	No	No
rattlesnake	Yes	No	No	No

As nouns, rattler and rattlesnake are synonyms defined as:

rattler and rattlesnake: pit viper with horny segments at the end of the tail that rattle when shaken

rattler (noun)	rattlesnake (noun)
pit viper with horny segments at the end of the tail that rattle when shaken	pit viper with horny segments at the end of the tail that rattle when shaken
a railroad train consisting of freight cars