"On the floor"

[Cyber-Ref]

I noticed a number of my more experienced partners use the vocal signal "On the floor" when calling certain fouls. It is usually around the basket, or in the lane, and mostly in the front court. It seems that this happens on a non shooting play where the offensive player in control is fouled by a defensive player before the shot.

The sequence goes like this:

1. Whistle
2. Fist goes up
3. Vocal signal...."On the floor"
4. Sometimes, not always a pointing gesture to the spot on the court where the foul occured.
5. Report to the table

Is this similar to saying "Before the shot"?

Is this a widely accepted mechanic?

Are there rules or cases to support this?

I'm curious as to the intent or meaning or the origin of this statement relating to calling thes types of plays.