Port is the left side of the boat. 


Starboard is the right side of the boat. If in a car, you say 'look to your right', on a boat, you say 'look to the starboard'. 


The bow is the front of the boat. 


Stern is the back of the boat.


The windward side of the boat is the side facing into the wind. So if the wind is coming from the right side, the windward side is on the right. A times you need to talk about a direction not fixed in relation to the boat, but rather relative to the direction of the wind.


Leeward side of the boat is the lee side. If the wind is coming from the right side, the leeward side is on the left. 


Helm is the boat's steering wheel. Tiller is the long stick that operates your boat's rudder. A steering stick, if you will. It has the same function as a helm does, but it is usually used on smaller boats, where a helm would take up too much space.


The rudder is the long, flat piece that sits underwater below the back of your boat. Connected to a tiller or a helm, it is moved to control the direction the boat is going.


Hull is the boat's body. Structures sitting on top of the deck, like a deck salon or cabins, aren't considered a part of the hull.


The keel is an underwater fin below the boat's belly. The sizes and shapes vary, sometimes it is relatively short and goes deep, (fin keel) sometimes it runs from the front all the way to the back (full keel or ballast keel). It is there mainly for stability and to help maintain forward direction when sailing.


The cockpit is the area where a boat is operated from. On sailboats, it is usually in the back and it is an open area without a roof, though this varies. You will find the rudder control and winches there.


The bimini is a sun roof or shade that is covers the cockpit, and is generally attached to a steel frame which runs over the cockpit.


Lines are ropes used for a specific purpose. There are more specific terms for certain lines like jib sheets and halyards.


The mainsail (or just the main) is the largest sail of the boat, attached to the mast on the side and the boom at the bottom. It has a triangular shape and serves as the most important sail. We flake the sail and secure it to the boom when not in use. Some mains roll into the mast.


The jib is the front sail of your boat, sometimes also called the genoa on the traditional sloop two sail setup you see the most often. The jib is wrapped around the shroud, the line that goes from the top of your mast to the boat's bow. The roller furler assembly is used to wrap it.


Spinnaker is the third type of sail you are the most likely to encounter. It goes in front of your boat and has a half balloon or kite-like shape and it is usually in bright colors. It is constructed specifically for sailing downwind (wind behind the boat).


The forestay is the cable going from the top of the mast to the very front of the bow. It is there to hold the mast in place. Sometimes you will hear people refer to it as the 'headstay'.


The backstay is the cable going from the top of the mast to the back of the stern. It is there to hold the mast in place.


The mast is the tall, vertical aluminum pole that goes from the floor of your salon, through the deck, above your boat. It is secured in placed by the standing rigging consisting of the shrouds, backstay and the forestay.


The boom is the horizontal pole right above the deck, attached to the mast at the right angle. The bottom of the mainsail is attached to it, it is used to determine its shape and direction. It is also where the mainsail is often stored, folded and covered with a protective sheet.


Halyard is the nautical name for lines or ropes that are used to raise and lower the sails. The halyard is attached to the top (or head) of the sails. You'll find halyards on both the mainsail and jib.


Sheet is the nautical term for lines or ropes that are used to set the angle of the sail.


The mainsheet traveler is a rail in the cockpit that is used to control the mainsheet and the mainsail angle.


Mainsheet is used to set the angle of the mainsail. The mainsheet is attached to the Mainsheet traveler. 


Jib Sheet comes with two sheets, one on each side of the boat. This prevents you from having to loosen your sheet, throwing it around the other side of the mast, and tightening it. The jib sheets are often controlled using winches.


Cleats are small on-deck hooks (looks like horns) that can be used to tie down sheets and lines after trimming them. Some of our boats have clutch type cleats and jams the line in on direction while allowing movement in the other direction.


Winches are mechanical spools that are used to easily trim lines and sheets. Most sailboats use winches to control the jib sheets.


Reefing lines run through the mainsail, used to put a reef in the main to reduce its area in strong winds.


Boom Topping Lift is a line that is attached to the aft (back) end of the boom and runs to the top of the mast. It supports the boom whenever you take down the mainsail.


Boom Vang (or a boom vang) is a device pulling the boom down. This is important because it controls the tension of the mainsail, influencing its shape greatly. 


Pulpits are fenced platforms on the sailboat's stern and bow, which is why they are called the bow pulpit and stern pulpit here. They typically have a solid steel framing for safety. 


Stanchions are the standing poles made of steel tubing to support the lifelines, which provide fencing around the sailboat's deck for safety. On most sailboats, steel cables are used for the lifelines, some with vinyl cover on the cable.


Shrouds are the cables going from the top of the mast to the left and right side of the boat. Sometimes there are four, two on each side. Together with forestay and backstay, they make sure your mast withstands all the forces exerted on it when the wind pushes the sails.

The foot of a sail is its bottom edge. If you imagine a sail as a triangle, the base is called the foot. 

Leech of a sail is its back side edge. Thus it is the part closest to you when you are standing at the helm.

Luff of a sail is its front side edge. Thus the part the furthest from you when you are standing at the helm. For mainsail, it is the edge that is right next to the mast, for the foresail it is the edge right next to the forestay. 

The head of a sail is its top corner. On a traditional sloop, you will have the 'main head' and the 'jib head'. There is usually a reinforcing patch of some kind on these corners, as you will find a hole in them to which a line is attached.

Clew of a sail is its back corner. The line attached to the 'main clew', called an outhaul, will be used to roll out your mainsail if it is wrapped inside of the mast. The line attached to the 'jib clew' will be used to open the jib on most sailboats since jibs are most often wrapped around the luff.

Outhaul is the line attached to the mainsail or the jib clew, allowing the control of the foot tension.

Telltales are light, usually cotton or wool pieces of ropes attached to a sail, showing you the airflow around it. These are important because they help you determine if your trim is effective or not.

Reefing is reducing the sail area to lessen the power exerted on it by the wind. You may want to reef if the wind is getting too strong for your boat, or if it is changing too rapidly, as an overpowered boat is difficult to control.

A batten is a slat placed horizontally in the body of the sail to support its shape. Sails tend to belly out and lose their shape under certain conditions.

Fenders are bumpers allowing some contact with other boats or piers while docked, without scraping the paint or damaging the hull.

The beam is the width of the boat at its widest point.

True wind is the actual direction and speed of the wind. This is different than the apparent wind, which is wind direction and speed relative to the boat. Apparent wind is a combination of the true wind and the headwind, which is the wind the boat experiences solely by being in motion.

The berth is a sleeping space on a boat.

Boat's draft is the distance from the water surface to the deepest point of the boat. In other words, the draft is the minimum water depth you can go to and not scrape your hull or keel.

Tacking is zig-zagging towards your destination by turning the bow thru the wind. It is necessary in case your destination is in the direction of the wind since sailboats cannot go directly into the wind. As the closest to the wind direction you can sail is around 45 degrees, you have to change direction left and right from your desired course.

The chart is a nautical map. It differs from classical maps as it depicts information relevant for a sailor - water depth, navigational hazards, seabed material, anchorages and so on. Charts are made to certain scale and can be used to measure distance precisely.

Galley on a boat is its kitchen.

Head on a boat is the bathroom.

A knot is the unit of speed of boats. 1 knot is to travel one nautical mile in an hour. That is 1.852 kilometers per hour or 1.1508 miles per hour. When we tie ropes, we are tying knots. That's a different usage of the same word.

Mooring is attaching the boat to a buoy that is anchored to the seabed.

A salon on a boat is its living room.

A skipper is the captain of a sailboat, also referred to as master of the vessel in nautical legalese.

A monohull is a classical boat with a single hull. A boat with two hulls is called a catamaran, or a cat. There are also trimarans, boats with three hulls.