
Port and starboard are
nautical terms for
watercraft and
aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines. ...
, referring respectively to the left and right sides of the vessel, when aboard and facing the
bow (front).
Vessels with bilateral
symmetry have left and right halves which are
mirror images of each other. One asymmetric feature is where access to a boat, ship, or aircraft is at the side, it is usually only on the port side (hence the name).
Side
Port and starboard unambiguously refer to the left and right side of the vessel, not the observer. That is, the port side of the vessel always refers to the same portion of the vessel's structure, and does not depend on
which way the observer is facing.
The port side is the side of the vessel which is to the left of an observer aboard the vessel and , that is, facing forward towards the direction the
vehicle
A vehicle (from la, vehiculum) is a machine that transports people or cargo. Vehicles include wagons, bicycles, motor vehicles ( motorcycles, cars, trucks, buses, mobility scooters for disabled people), railed vehicles ( trains, trams ...
is heading when
underway, and starboard side is to the right of such an observer.
This convention allows orders and information to be given unambiguously, without needing to know which way any particular crew member is facing.
Etymology

The term ''starboard'' derives from the
Old English ''steorbord'', meaning the side on which the ship is steered. Before ships had
rudders on their centrelines, they were steered with a
steering oar at the
stern of the ship on the right hand side of the ship, because more people are
right-handed.
The "steer-board" etymology is shared by the
German ''Steuerbord,''
Dutch ''stuurboord'' and
Swedish
Swedish or ' may refer to:
Anything from or related to Sweden, a country in Northern Europe. Or, specifically:
* Swedish language, a North Germanic language spoken primarily in Sweden and Finland
** Swedish alphabet, the official alphabet used by ...
''styrbord'', which gave rise to the
French
French (french: français(e), link=no) may refer to:
* Something of, from, or related to France
** French language, which originated in France, and its various dialects and accents
** French people, a nation and ethnic group identified with Franc ...
''tribord'',
Italian ''tribordo,''
Catalan
Catalan may refer to:
Catalonia
From, or related to Catalonia:
* Catalan language, a Romance language
* Catalans, an ethnic group formed by the people from, or with origins in, Northern or southern Catalonia
Places
* 13178 Catalan, asteroid ...
''estribord'',
Portuguese ''estibordo'', Spanish ''estribor'' and
Estonian ''tüürpoord''.
Since the steering oar was on the right side of the boat, it would tie up at the
wharf
A wharf, quay (, also ), staith, or staithe is a structure on the shore of a harbour or on the bank of a river or canal where ships may dock to load and unload cargo or passengers. Such a structure includes one or more Berth (moorings), berths ...
on the other side. Hence the left side was called ''port''. The ''
Oxford English Dictionary
The ''Oxford English Dictionary'' (''OED'') is the first and foundational historical dictionary of the English language, published by Oxford University Press (OUP). It traces the historical development of the English language, providing a com ...
'' cites ''port'' in this usage since 1543.
Formerly, ''larboard'' was often used instead of ''port''. This is from
Middle English
Middle English (abbreviated to ME) is a form of the English language that was spoken after the Norman conquest of 1066, until the late 15th century. The English language underwent distinct variations and developments following the Old English ...
''ladebord'' and the term ''lade'' is related to the modern ''load''.
[ ''Larboard'' sounds similar to ''starboard'' and in 1844 the ]Royal Navy
The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by Kingdom of England, English and Kingdom of Scotland, Scottish kings from the early medieval period, the first major maritime engagements were foug ...
ordered that ''port'' be used instead. The United States Navy followed suit in 1846. ''Larboard'' continued to be used well into the 1850s by whalers. In chapter 12 of ''Life on the Mississippi'' (1883) Mark Twain writes ''larboard'' was used to refer to the left side of the ship (Mississippi River steamboat) in his days on the river – circa 1857–1861. Lewis Carroll rhymed ''larboard'' and ''starboard'' in "Fit the Second" of '' The Hunting of the Snark'' (1876).
An Anglo-Saxon record of a voyage by Ohthere of Hålogaland used the word "bæcbord" ("back-board") for the left side of a ship. With the steering rudder on the starboard side the man on the rudder had his back to the bagbord (Nordic for portside) side of the ship. The words for "port side" in other European languages, such as German ''Backbord'', Dutch and Afrikaans ''bakboord'', Swedish ''babord'', Spanish ''babor'', Portuguese '' bombordo'', Italian ''babordo'', French ''bâbord'' and Estonian ''pakpoord'', are derived from the same root.
Importance of standard terms
The navigational treaty convention, the International Regulations for Preventing Collisions at Sea—for instance, as appears in the UK's Merchant Shipping (Distress Signals and Prevention of Collisions) Regulations 1996 (and comparable US documents from the US Coast Guard)—sets forth requirements for maritime vessels to avoid collisions, whether by sail or powered, and whether a vessel is overtaking, approaching head-on, or crossing.[ To set forth these navigational rules, the terms starboard and port are essential, and to aid in '' in situ'' decision-making, the two sides of each vessel are marked, dusk to dawn, by navigation lights, the vessel's starboard side by green and its port side by red.][ ]Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines. ...
are lit in the same way.
See also
* Anatomical terms of location
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position ...
, another example of terms of directionality that do not depend on the location of the observer for things that are bilaterally symmetrical
* Dexter and sinister
* Direction (disambiguation)
* Glossary of nautical terms
* Handedness
In human biology, handedness is an individual's preferential use of one hand, known as the dominant hand, due to it being stronger, faster or more dextrous. The other hand, comparatively often the weaker, less dextrous or simply less subjec ...
* Laterality
* Proper right and proper left
* Reflection symmetry
* Sinistral and dextral
Notes
References
{{Aircraft components, state=collapsed
Aeronautics
Nautical terminology
Orientation (geometry)