Sailing terms and nautical glossary
Find clear definitions of sailing terms, boat parts, knots, navigation and nautical abbreviations. New to sailing? Start with the everyday words below, then explore the full glossary by subject or search for a term.
Sailing terms for beginners
Begin with port and starboard, bow, windward and leeward. Learn how sheets and halyards control sails, then explore points of sail, tacking and gybing.
For terms in context, read our beginner sailing vocabulary guide. Ready to practise on the water? Our first sailing course guide explains how to choose a starting route.
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TermDefinition
- General Nautical Terminology, Nautical Topics, Navigation, Organisation, Signals & Communication IALA
The intergovernmental organisation that develops international guidance and cooperation for marine aids to navigation.
IALA produces...
More Details - General Nautical Terminology, Nautical Topics, Navigation IALA Region A
The maritime buoyage region in which port-hand lateral marks are red and starboard-hand lateral marks are green when following the conventional...
More Details - General Nautical Terminology, Nautical Topics, Navigation IALA Region B
The maritime buoyage region in which port-hand lateral marks are green and starboard-hand lateral marks are red when following the conventional...
More Details - Courses, General Nautical Terminology, Nautical Topics, Navigation, Organisation ICC
A certificate demonstrating pleasure-craft competence in specified categories for use where an authority or operator recognises it.
The ICC...
More Details - General Nautical Terminology, Nautical Topics, Safety, Signals & Communication Code Flag India (I)
An International Code of Signals flag whose single-letter meaning is “I am altering my course to port.”.
The India flag may be displayed alone...
More Details - General Nautical Terminology, Nautical Topics, Organisation, Weather (Meteorology) ICON
A global and regional numerical weather and climate modelling framework using an icosahedral triangular grid and nonhydrostatic dynamics.
ICON...
More Details - General Nautical Terminology, Nautical Topics, Organisation, Weather (Meteorology) ICOsahedral Nonhydrostatic Model (ICON) (ICON)
A global and regional numerical weather and climate modelling framework using an icosahedral triangular grid and nonhydrostatic dynamics.
ICON...
More Details - General Nautical Terminology, Nautical Topics, Organisation, Safety, Signals & Communication ICS
An internationally standardised system of flags, radiotelephony and coded signals for communicating important maritime messages, particularly...
More Details - General Nautical Terminology, Nautical Topics, Navigation, Organisation IDL
A conventional boundary near 180° longitude across which the civil calendar date changes by one day.
It bends around countries and island...
More Details - General Nautical Terminology, Nautical Topics, Depths & Clearance, Navigation, Organisation IHO
An intergovernmental organisation that coordinates international hydrography and standards for nautical charts and marine geospatial...
More Details - General Nautical Terminology, Nautical Topics, Signals & Communication Letter I (Flag Semaphore)
A two-flag semaphore position representing the letter I.
The signaller holds one flag in each hand at the prescribed angles illustrated in the...
More Details - General Nautical Terminology, Nautical Topics, Signals & Communication Letter I (Morse Code)
The International Morse Code letter I, represented by dot dot (..).
A dot lasts one signal unit and a dash three. Elements within this...
More Details - General Nautical Terminology, Nautical Topics, Navigation, Organisation, Safety IMO
The specialised United Nations agency responsible for global standards concerning the safety, security and environmental performance of...
More Details - General Nautical Terminology, Nautical Topics, Organisation, Safety, Signals & Communication IMO Standard Marine Communication Phrases (SMCP) (SMCP)
A standardised set of English phrases for safety-related ship-to-ship, ship-to-shore and onboard communication.
The IMO adopted the SMCP to...
More Details - General Nautical Terminology, Nautical Topics, Parts of a Boat, Safety Impeller
A rotating component with blades or vanes that transfers energy between a shaft and a fluid.
In centrifugal pumps the impeller accelerates...
More Details - General Nautical Terminology, Nautical Topics, Maritime Language & Traditions Impressment
The historical compulsory recruitment of people into naval service by state authority.
It is particularly associated with the British Royal...
More Details - Courses, General Nautical Terminology, Nautical Topics, RYA, Points of Sail, Safety Improve your Wingsurfing
An RYA practical course consolidating wing control, board handling and independent non-foiling wingsurfing.
It develops stronger upwind and...
More Details - General Nautical Terminology, Nautical Topics, Phonetic Alphabet, Signals & Communication India
The standard spoken code word for the letter I in the international radiotelephony spelling alphabet.
It is pronounced “IN-dee-ah” and is used...
More Details - General Nautical Terminology, Nautical Topics, Parts of a Boat, Points of Sail, Safety Inhauler
A sail-control line that pulls a sheet lead or sail clew inboard.
On a headsail, an inhauler narrows the sheeting angle and can alter slot...
More Details - General Nautical Terminology, Nautical Topics, Navigation, Points of Sail, Safety In Irons
Unable to complete a tack because a sailing vessel has lost drive while pointing into or very close to the wind.
With the sails luffing and...
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