Tremolo - EP - was created in 1990.

The Heart's Tremolo was created in 1994.

There was a tremolo effect the way Makayla was playing her flute

Wide Swing Tremolo was created on 1998-10-06.

A tremolo arm is what allows one to use a tremolo. A tremolo is a mechanism in a stringed instrument that allows changing the pitch of all the strings simultaneously.

The major drawback of a tremolo is that large amounts of use will stretch the strings and throw the instrument out of tune, requiring the player to have to continually retune the instrument. The idea behind the Floyd Rose brand tremolo is to alleviate this problem by locking the strings at both the nut and the bridge. More details on the Wikipedia page here: http://en.wikipedia.org/wiki/Floyd_Rose