Where the ball's come to rest may be just not true! (3)
I believe the answer is:
lie
'where the ball's come to rest may be just not true' is the definition.
The answer is a location as well as being a singular noun. This is suggested by the definition.
This is the entire clue.
Can you help me to learn more?
(Other definitions for lie that I've seen before include "Perversion of the truth" , "Tell porkies" , "A white one is considered harmless" , "Disinformation" , "Tell tales" .)