This sail is luffing. What does that mean? (Courtesty of Tim Kent)

There are many technical terms for the parts of a boat and the maneuvers of sailing. Some important sailing terms and their definitions are given here.

ABEAM: Off to the side; 90 degrees from the bow.

AFT: At or toward the stern.

ASTERN: Behind a boat; backward.

ATHWARTSHIPS: At right angles to the fore-and-aft line of the boat.

BALLAST: A weight in the centerboard or keel that helps provide stability.

BATTENS: Long, thin pieces of wood inserted in pockets along the leech of a sail, used to help the sail keep its proper shape.

BEAM: The width of a boat at its widest point.

BILGE: The curved part of the hull below the waterline. Also, the inside of the hull at the very bottom of the boat.

BLOCK: A frame with grooved rollers or pulleys for hauling lines.

BOOM: The pole attached at right angles to the lower part of the mast. The foot of a sail is fastened to it.

BOW: The front of the boat.

BUOY: A floating marker used for navigation.

CAPSIZE: To overturn.

CENTERBOARD: A flat wooden or fiberglass fin let down into the water under the boat from inside a box in the center of the boat. It gives the boat stability and keeps the boat from slipping sideways when going windward.

CLEAT: A metal or wood fitting with two projecting horns or arms, around which lines are secured.

CLEW: The lower outside, or after, corner of a sail.

COCKPIT: The area where the crew sits and the tiller is located.

DINGHY: A small boat, often carried or towed by a larger boat, which is used to get to and from shore.

FOOT: The lower edge of a sail.

FORE-AND-AFT: From front to back; lengthwise.

HALYARD: A line for hoisting a sail.

HEEL: To tilt sideways.

HULL: The body of the boat.

KEEL: A fixed and weighted lead or metal projection, usually V-shaped, from the center of the bottom of the boat down into the water. The keel provides stability.

LEECH: The outside, or after, edge of a sail.

LEEWARD: Away from the wind; the sheltered side.

LUFF: The front edge of a sail; the flapping of sails.

OUTHAUL: A line used to haul the foot of a sail taut along a boom.

PAINTER: A line fastened to the bow of a small boat, used for tying it up to a pier or a mooring.

PORT: The left side of the boat, as you face forward.

QUARTER: The part of the boat between the beam and the stern.

RAIL: The outer side of the boat's deck.

RUDDER: The device that swings in the water at the stern of a boat. It is attached to the tiller and controls the steering of the boat.

SHEAVE: A roller set in a block, often at the top of a mast or the end of a boom, over which a line such as a halyard or an outhaul runs.

SHEET: A line used to trim a sail. A sheet takes the name of the sail it controls, for example, mainsheet, such as jibsheet, and so on.

SHROUDS: Wires or lines that support the mast athwartships.

SPARS: The booms, gaffs, and masts of the boat.

STARBOARD: The right side of the boat, as you face forward.

STAY: Wires or lines that support the mast from bow to stern.

STERN: The rear part of the boat.

TILLER: The wooden arm attached to, and used to control, the rudder of the boat. Some boats have a wheel for steering.

TOPSIDE: The part of the boat between the waterline and the rail.

TRANSOM: The flat or slightly curved surface across the stern of the boat.

WINCH: A mechanical drum, often with a handle, used to pull in sheets and halyards.

WINDWARD: On the side toward the wind; in the direction from which the wind is blowing.