Bilge
The lowest part of a boat interior, where water is likely to collect. When necessary, it is drained with the bilge pump.

Boat hook
A pole fitted with a blunt hook at one end, used during  mooring.

Boom
Horizontal beam attached to the mast by means of a stopper that runs on a groove, determining its height with respect to the mast.

Bottom
The part of the boat which is permanently immersed in water

Bow
The forwardmost or front part of a boat.

Bowsprit
A boom that extends from the bow nearly horizontally, to which the jib is attached

Bulwarks
The part of a ship’s side that extends above the main deck to protect it against heavy weather

Buoy
An anchored float marking the position of an object on the sea bottom, or for use as mooring.

Catch (to)
To hold onto a line, or to catch the wind and sail close hauled.  Also used when the anchor has gripped the bottom.

Charter  
Rental of a boat, either with a skipper or not

Come about (to)
To bring the boat from one tack to the other when sailing into the wind, by turning through the eye of the wind, so that the sail is flown in the opposite side.

Companion way
The area leading down from the deck to the cabin: by extension, also its sliding cover.

Course
The prescribed compass direction in which the boat is being steered. To set course
To head the boat to a prescribed bearing; Collision course: If not modified, this course could result in collision with another boat

Cutter 
Originally an English vessel, small and very swift due to its large sails, 40 feet long and rigged with a bowsprit and square sails.  Today, a boat rigged with more than 1 jib.

Deadwork, topside
The part of the boat which is above the waterline.

Draw up alongside, to board
To approach, with a ship, the side of another ship. To go onboard a ship. 

Ease (to)
To let out a line or sail; to relieve tension on a line.

Echo sounder
Instrument used to determine the distance between the boat bottom and the sea bottom, through the emission of a sound wave and the reception of its echo.

Fender
A cylindrical or spherical protective cushion of  durable material, hung from the sides of a boat.

Floorboards
Inner flooring of a boat, made of movable wooden planks 

Foot
Length measure unit, equivalent to 30,48 cm, used in defining boat length.

Fore mast
The forward mast of a boat with three masts; it is rigged with a fore stay sail.

Furling line
Line used for securing a rolled sail to its main support

Gybe (to)
To turn the boat so that the stern crosses the wind and the boom passes on the other side of the boat, thus changing direction.

Haul aft (to)
To tighten a line in order to adjust the position of the sails

Jib
The foremost sail.  A triangular shaped foresail forward of the foremast, rigged onto the stay. A large foresail, overlapping the mainsail, is called a genoa because it was allowed for sailing competitions (leading to victory the Swedish sailor Sàlen), in the Genoa Regatta of 1926.

Locker
A closet or storage space for storing boating equipment and personal objects.
Luff up (to)
To steer the boat more into the wind, thereby causing the sails to flap or luff

Mainsail
Generally the largest sail – it is the principal sail, set on the main mast and the boom.

Mast
A vertical spar on a sailing vessel employed as the support for the sails. It is placed in a vertical position or slightly inclined toward the stern, and  has different names according to its position, for example: foremast, mizzenmast, main mast, or signal mast.

Pantry
In large ships it is the room where food is stored – by extension, the term is also used to indicate the food items bought for a trip

Pilot-boat
A small boat used to assist larger boats in navigation, when entering or leaving a port or bay.

Pleasure boating
Boating for sport and leisure, not for business.
The Italian law defines 3 categories of vessels:  ships, boats and crafts, in relation to length and tonnage.

Pulpit
An elevated guardrail set up at the bow of a boat.  When erected at the stern, it is called a pushpit.

Quickwork, hull
The part of the boat which is below the waterline.

Reefing Line
Small line used for hoisting sails to the yard or for reefing.

Rig  (to)
To furnish the boat with everything necessary for navigation.

Round (to)
To go around a cape, promontory or buoy during navigation.

Sailing directions
Publications that describe features of a sailing area, with indications on harbours, bottom types, services, rules and regulations, hazards and dangers.  It complements the nautical charts required for navigation.

Sea cock
Underwater opening in a ship’s hull, at the end of a water pump duct.  During navigation, all sea cocks must be closed to prevent sea water from entering the boat.

Sheet
A line that controls the angle of a sail in relation to the wind, attached to the clew of the sail to adjust its trim.  It takes its name from the sail it controls (jib sheet, main sheet..)

Shrouds
Steel cables supporting the mast laterally by running from the top of the mast to the side of the boat.  They also help to lessen rigging tensions.

Signal fires
Part of the obligatory safety devices of a ship, they are used in case of danger if help is needed.

Signal flags (international code flags)
Each letter of the alphabet corresponds to a flag – with specific colours and patterns – and with a specific meaning.  For example, letter T corresponds to a red, white and blue flag with 3 vertical bands, and means “I am fishing, stay away”.

Skipper
The captain or master of a ship.

Starboard
Looking towards the bow, it is the right side of a boat.

Stays
Steel cables used to support the sails, or forming the protection railing of a boat.

Stern
The back (aftermost) part of a boat.

Stop (to)
To block the running of a line or chain, often with a lever device called stopper.

Reef
A part of a sail that can be rolled up – in order to reduce the sail area in heavy winds – and tied with reef lines which are sown onto the sail itself.

Tack
The direction that a boat is sailing in relation to the wind.

Topping lift
A line that holds up the boom when the mainsail is not hoisted.

Waterline
The line where the water comes to on the hull of a boat

Winch
A metal drum shaped device, rotating only in one direction, used when raising or trimming sails, loading and discharging cargo or hauling in lines.