What ever sport or activity you do, the chances are that there is some special jargon for describing things. Sailing is no different and it has it's fair share. Part of learning to sailing is just getting to know the jargon so that you can at least talk to talk (or know what people are talking about) even if you are learning to walk. This glossary of jargon describes most things and is a good place to start.
 
(Important things include a * )

AFT The back of the boat.

ASTERN Behind the boat.

BEAM Bars that hold the two hulls apart; widest part of the boat.

*BEAT To sail upwind or into the wind

*BOOM Pole extending horizontally from the mast, attached to the bottom of the mainsail and is used to help pull the sail in and out.
 

*BOW The front of the boat.

BOWSPRIT A small pole that comes out from the front of the boat and used to hold the gennaker in place.
 
COCKPIT Hollowed out space where the crew sits when the hull is out of the water.

CREW The competitors.

*DAGGERBOARD A retractable fin (one for each hull) that can be lowered beneath the hull and prevents the boat from slipping sideways.

DNF An abbreviation used when a boat ‘did not finish’ a race.

*DOWNWIND To sail away from the wind ie the wind is coming from behind.
 

DSQ An abbreviation meaning a boat was ‘disqualified’ from a race.

FURL To roll or fold a sail.
 
GENNAKER An asymmetric sail used downwind and is the biggest sail on the boat.
 

*GYBE To change direction by turning the stern of the boat through the wind that is coming from behind ie downwind.
 

*HALYARD A rope used to pull up a sail.

*HELM The person who steers the boat.
 

HIKE To use crew weight to keep the boat flat by leaning out of the boat.

*HOIST To raise a sail.
 
*JIB The smallest sail at the front of the boat, used upwind.
 

*KNOT Measurement of speed referring to nautical miles per hour for boat and wind speed. 1 knot = 1.15 mph/ 11.1kmp
 

*MAINSAIL The principal sail on a boat attached to the mast leading towards the back of the boat.

*MAINSHEET The rope that adjusts the mainsail.

*MAST A vertical pole that is attached to the hull and carries the sails.

OCS An abbreviation used when a boat is on course side before the official starting signal is blown.

PORT The left side of the boat when facing forward.
 

*REACH Sailing across the wind.

REEF To reduce the area of the sail.

RIG Refers to the mast and boom; the structure that holds the sails up.
 

*RUDDER A fin attached to the back of the boat and sits in the water to steer the boat.

*SHEET Rope used to pull the sails in or out.

STARBOARD The right side of the boat when facing forwards.

STERN The back of the boat.

*TACK To turn the bow of the boat through the wind.

*TILLER The handle used to move the rudder.

 
TRAMPOLINE The mesh area between catamaran hulls.

*TRIM To adjust the sails depending on the wind angle.
 
UPWIND Sailing towards or into the wind.
 
WINCH A metal drum that takes the load when trimming the sails.

*WINDWARD The side of the boat closest to the wind.