What does it mean to "Call an audible"?

Question

What does it mean to "Call an audible"?

Answer 1

Literally, to change the play, basically at the last minute, as in American football. You go in with one plan, you see a set of circumstances that might be disadvantageous to the execution of that plan, so you change things up.

Answer 2

In football, the quarterback calls the play in the huddle. Sometimes when he gets to the line of scrimmage, he looks at the defense and decides he needs to change the play call. So, he yells a new play to his offensive line at the line of scrimmage. This is 'calling an audible."

Answer 3

That means you are changing the play at the line of scrimmage, owing to an alteration in what you can see coming at you