Definitions of rattle:

• noun:   loosely connected horny sections at the end of a rattlesnake's tail
• noun:   a baby's toy that makes percussive noises when shaken
• noun:   a rapid series of short loud sounds (as might be heard with a stethoscope in some types of respiratory disorders)

  Example: "The death rattle"

• verb:   make short successive sounds
• verb:   shake and cause to make a rattling noise