There is specialised terminology and language associated with many professions. In boating this is more pronounced, it has its own language, evolved over centuries to suit the needs of seafarers.

Understanding this terminology is important as it underpins boating knowledge and seamanship skill.

Term  Description 
Abeam At 90 degrees to the vessel's direction or fore and aft line. 
Aft Towards the back/stern of the boat.
Astern In the back of the boat.
All-round light A light showing an unbroken light over an arch of the horizon of 360 degrees. A masthead light located on power vessels is an all-round light.
Bar A shallow area formed by sand, mud, gravel, or shingle, near the mouth of a river or at the approach to a harbour which is often dangerous.
Beam The greatest width of the boat.
Bow The front of the vessel.
Bowline Knot used to form a loop in the end of a line.
Bitter end The last part of the rope or chain which should be connected to the inside of the anchor locker.
Buoy A floating container anchored to the sea bottom so that it remains in position. Buoys are used to mark channels, moorings , exclusion zones or racecourses. 
Bombora A shallow area where waves may break.
Chart Datum The baseline of tidal height above which tidal levels and predictions are given in Tide Tables.
COLREGS International rules for the prevention of collisions at sea. The rules of the road at sea.
Come to Point up closer to the wind.
Draft The minimum depth of water a vessel needs to float in.
Ebb tide A falling or run-out tide.
Enclosed waters Any port or navigable waterway.
EPIRB Emergency Position Indicating Radio Beacon
Fairway Any navigable channel.
Flood tide The rising or run-out tide.
Freeboard The distance from the waterline to the deck.
Give-way Reduce speed, stop, go astern or alter course so as to keep out of another vessels path.
Go astern Reverse engines or travel backwards
Gunwale Pronounced "gunnel", the top each of the vessel's sides.
Heave to Steering into the wind and sea making minimum headway
Knots (speed) One knot is a speed of one nautical mile per hour or 1.852km/hr.
Lanyard A small line used to join to anything. Example: bucket
Leads (transits) Marks used in channels and at bar entrances which when in line indicate the centre of the navigable channel.
Lee shore The shore onto which the wind blows.
Leeward The downwind side.
Magnetic north This is where all compass needles point. It is the area of greatest magnetic attraction in the earth.
On the quarter Towards the stern, not abeam.
Open waters Navigable waters which are not enclosed waters. Often referred to as "Ocean waters".
Planing A boat is said to be planing when it is moving over the top of the water rather than through the water.
Port -side The left-hand side of a vessel when you are looking forward from the stern and the side on which a red navigation side light is displayed.
PWC Personal water craft is vessel designed to be operated by a person standing, siding astride or kneeling on. It uses waterjet propulsion and has an engine in a watertight compartment.
Quartering Sea Sea coming on a boats quarter.
Scope The ratio of length of anchor rode in use to the vertical distance from the bow of the vessel to the bottom of the water
Spring line A pivot line used in docking, undocking preventing the boat from moving forward or astern while made fast to a dock/jetty.
Stand on Continue on the same course and speed.
Starboard side The right hand side of the vessel when you are looking forward from the stern and the side on which a green navigation side light is displayed.
Stern The back or rear of the vessel.
Transom The stern cross-section of a boat.
Trim Fore and aft balance of a boat
Underway Not at anchor or made fast to shore or ground. If you are drifting, you are underway.
Windward The direction from which the wind blows.