What is rotating?

I've barely scratched the surface of competitive CS:GO, but from what I've heard, the phrase "rotating" is shouted out a lot.

What exactly do players mean when they say "rotating". Does this mean players on another team are swapping roles? Or does it mean that they're moving from one Bombsite/Hostage to another?

Solution 1:

Rotating is effectively moving between points of interest on the map - this could be bomb sites, hostage locations, locations where a team mate just died, or other mission objective.

It's not specific to Counter Strike. Use the following map of de_dust2 as an example;

While the routes may not be exact, rotating on this map would generally indicate moving between the bomb sites marked with red X's.

Solution 2:

I have no experience of Counter Strike competitive, but I have watched matches. So, for example you're a terrorist.

You're in Bomb Site A with the bomb, and someone from the enemy team spots you heading there. You will need to "rotate" to Bomb Site B since you'll get killed in A. Basically, it is going to another place in the map from where you are.