From A Wiki of Ice and Fire
The Three Whores are three great trebuchets built inside the Mud Gate in King's Landing.
A Clash of Kings
The trebuchets are called the Three Whores by members of the gold cloaks because they are supposed to give Stannis Baratheon a lusty welcome when he comes to attack King's Landing in the Battle of the Blackwater.
- ↑ A Clash of Kings, Chapter 49, Tyrion XI.