Audible
Part of speech: adjective
Definition: Able to be heard.
Part of speech: verb
Definition: To change the play at the line of scrimmage by yelling out a new one.
Part of speech: noun
Definition: The act of or an instance of changing the play at the line of scrimmage by yelling out a new one.
Perceptible
Part of speech: adjective
Definition: Able to be perceived, sensed, or discerned.