Boom

   A horizontal pole or spar to which the bottom of a sail is attached.

   Catamaran

   A boat with parallel twin hulls.

   Centerboard

   A movable, fin-shaped protrusion under the hull that prevents a boat from sliding sideways and is used to right capsized dinghies.

   Dinghy

   A small sailing boat, rowing boat or ship's tender.

   Europe dinghy

   A single-handed centreboard dinghy class, often called "the small Finn", which is the smallest Olympic-class boat and is used for women-only competition.

   Finn

   A single-handed centreboard dinghy class used for men-only competition in the Olympic Games.

   49ER

   A double-handed, high-performance dinghy class with a low hull and tiny wings, by skiff standards, used for open competition in the Olympic Games.

   470

   A double-handed dinghy class used for men's and women's competition in the Olympic Games.

   Genoa

   The larger triangular forward sail in a sloop-rigged yacht.

   Jib

   The smaller triangular forward sail in a sloop-rigged boat.

   Keel

   A fixed, fin-shaped protrusion on the bottom of the hull that prevents a boat from sliding sideways.

   Keelboat

   A sailing yacht with a fixed keel.

   Kite

   Colloquial for "spinnaker", a large, billowing, often colourful sail used to obtain greater boat speed during downwind sailing, usually set in front of or instead of the jib and carried by the 470, 49er and Soling Olympic classes.

   Laser

   A single-handed centreboard dinghy class, the most popular one-design class in the world, used for open competition in the Olympic Games.

   Mainsail

   The larger sail behind the mast.

   Mainsheet

   The rope which controls the movement of a mainsail.

   Mistral

   A one-person sailboard known by its brand name and used for men's and women's events in the Olympic Games.

   Sailboard

   A lightweight, polyurethane, surfboard-like craft with a mast, boom and sail, on which the rider stands to manoeuvre; also known as a "windsurfer".

   Sheet

   A rope used to control and tension the sail and rigging.

   Skiff

   A light, open, small sailing boat or, more broadly, a boat with an open, self-draining hull.

   Sloop rig

   A sail plan composed of two sails - a mainsail and a jib, or genoa.

   Soling

   A three-person keelboat, the longest and heaviest of the Olympic-class boats, used for open competition.

   Sonar

   A three-person keelboat used for open competition in the Paralympic Games.

   Spar

   A general term referring to a boat's mast, boom and spinnaker pole, usually of an aluminium and/or carbon-fibre composition.

   Spinnaker

   A large, billowing, often colourful sail used to obtain greater boat speed during downwind sailing, usually set in front of or instead of the jib and carried by the 470, 49er and Soling Olympic classes.

   Star

   A two-person keelboat much lighter than the Soling and used for open competition in the Olympic Games.

   Stay

   A strong rope, commonly made of wire, used to support a mast.

   Tiller

   A handle attached to the rudder and used by the skipper to control steering.

   Tornado

   A two-person catamaran class that ranks as the fastest Olympic-class boat and is used in open competition in the Olympic Games.

   Trapeze

   A harness device worn by sailors on some dinghy, skiff or catamaran classes of boats which, with a metal stay from the mast, lets them lean almost completely outboard.

   2.4MR

   A single-handed, deep-displacement keelboat class used for open competition in the Paralympic Games.

   Windsurfer

   A lightweight, polyurethane, surfboard-like craft with a mast, boom and sail, on which the rider stands to manoeuvre; also known as a "sailboard".

Credit: IOC

For further info., please visit http://www.olympic.org/uk/sports/programme/disciplines_uk.asp?DiscCode=SA.