It holds (supports) the sails.
You can also mount navigation systems on it.
a pole on a sailboat is a mast
Mast
The Mast
It is called the mast
Is called a mast
Do you mean the mast?
masthead
Mast
sailboat spars include the: mast boom sprit (if the boat has one)
Mast?
The Mast
the snark