In Pool and Snooker, what does the term free ball mean?

If you are snookered following a foul shot by your opponent the refree will award a free ball which allows you to name and to pot any other ball on the table as if it was the or one of the balls on which you are snookered.

Example: you are snookered on all the reds following a fouls shot by your opponent. you are then allowed to nominate any colour for example yellow and pot this which will count as a red (1 point) then you can pot a colour and continue you break with a normal red.

The idea is that a player should not be disadvantaged by a snooker resulting from a foul shot - this prevents bad gamesmanship.

In pool it is similar so that you can strike one of your opponents balls (and pot it if you like) and continue by potting one of your balls.

I have heard that you cannot have a free ball if you are on the black but I am not 100% sure if this is a hard and fast rule.

In pool a free ball means you can hit your opponents ball or the black if you want and in snooker it means all balls are effectively counted as a red and count as one point

In Snooker, I believe it means that any ball on the table can be treated as a red ball, and is worth one point.

it means you have a free ball go for whatever