When something rattles or when you rattle it, it makes short sharp knocking sounds because it is being shaken or it keeps hitting against something hard.

A rattle is a baby's toy with loose bits inside which make a noise when the baby shakes it.

A rattle is a wooden instrument that people shake to make a loud knocking noise at football matches or tribal ceremonies.

A rattlesnake's rattle is the hard part at the end of its tail which makes a rattling sound when it is shaken.

If something or someone rattles you, they make you nervous.

You can say that a bus, train or car rattles somewhere when it moves noisily from one place to another.