What does "Mockingbird" mean ?

It's a kind of bird that imitates the sounds in its environment in order to delineate its territory.

There are several American songs that reference the mockingbird, the most famous of which are "Listen to the Mocking Bird" and "Hush Little Baby." Carly Simon made the song "Mockingbird" popular in the 70's; its lyrics are based on "Hush Little Baby."

well it's a bird that sometimes copies what people say and can imitate a cell phone ringing, etc.

"To Kill a Mockingbird" was a book/movie i think.

A mocking bird is a bird that does nothing but sing and doesn't harm anyone. Killing a mocking bird was looked down upon.