abandon - A race that a race committee or protest committee abandons is void but may be resailed. (ISAF Rules)

aft - toward the back of the boat.

apparent wind - the direction the wind seems to be coming from.  The apparent wind is the combination of the real wind and the wind caused by the forward motion of the boat.

athwartships - across the boat, from side to side

barging - Refusing to yield to the leeward boat at the starting line. 

The buoy room rule does not apply at a starting mark.

beam - The maximum width of a boat.

bear off - To head away from the wind, to go more to leeward.  If your sail is luffing, you may want to bear off.

beat - Going up wind by sailing back and forth.

block - A pulley

boom - The rod along the bottom of the sail.

bow - The front of the boat.

bowline - The most commonly used non-self-tightening knot.  This knot is often used to tie up a boat since even if the boat pulls on the knot, you can still get it loose.

break an overlap - When two boats stop having any part of them side by side. 

If you lose your overlap inside the three boat length circle, you still have the right of way.

bridle - A rope or wire on which the end of the main sheet slides.

broach - Turning suddenly and unintentionally broadside to the wind. 

broad reach - the wind comes directly from the side.

Sometimes in strong winds, to avoid broaching you need to put your daggerboard partly down when running.

buoy room -