"a bay, cove, inlet, or recess of a large body of water where vessels can load and unload and find shelter from storms; a harbor, whether natural or artificial," Old English port "a port, harbor, a place where there is a constant resort of vessels for the purpose of loading and unloading;" also "a town, market town, city," reinforced by Old French port "harbor, port; mountain pass." The Old English and Old French words both are from Latin portus "a port, harbor," figuratively "haven, place of refuge, asylum" (in Old Latin also "a house;" in Late Latin also "a warehouse"), originally "an entrance, a passage," akin to porta "a city gate, a gate, a door" (from PIE *prtu- "a going, a passage," suffixed form of root *per- (2) "to lead, pass over").
[I]in law, a place where persons and merchandise are allowed to pass into and out of the realm and at which customs officers are stationed for the purpose of inspecting or appraising imported goods. In this sense a port may exist on the frontier, where the foreign communication is by land. [Century Dictionary]
The figurative sense "place, position, or condition of refuge" is attested in English from early 15c.; phrase any port in a storm, indicating "any refuge is welcomed in adversity," is by 1749. A port of call (1810) is one paid a scheduled visit by a vessel in the course of its voyage. The verb meaning "to carry or bring into a port" is by 1610s.
c. 1300 (mid 13c. in surnames), porte, "a gate, an entrance to a place, a portal; the gate of a town or fortress," also in names of specific gates, from Old French porte "gate, entrance," from Latin porta "a city gate, a gate; door, entrance," akin to portus "harbor," from PIE root *per- (2) "to lead, pass over." Old English also had occasional port in this sense, from Latin, but the Middle English word seems to be a new borrowing via French.
The meaning "porthole, an opening in the side of a ship" is attested from mid-14c.; in old warships, an embrasure in the side of the ship through which cannons are pointed. The medical sense of "place where something enters the body" is by 1908 probably short for portal. In computers, "place where signals enter or leave a data-transmission system," by 1979, from earlier use in electronics (1953) for "pair of terminals where a signal enters or leaves a network or device," which also probably is short for portal.
"bearing, mien, carriage, demeanor, deportment," c. 1300, from Old French port "carriage demeanor," from porter "to carry," from Latin portare "to carry" (source of port (v.2)), from PIE root *per- (2) "to lead, pass over." From c. 1400 as "external appearance;" by 1520s in the now-archaic sense of "state, style, establishment."
type of sweet dark-red wine, 1690s, shortened from Oporto, the city in northwest Portugal from which the wine originally was shipped to England; the name is originally O Porto "the port, the harbor" (see port (n.1)).
"to carry, bear, convey," 1560s, from French porter, from Latin portare "to carry, bear, bring, convey," also figuratively, "betoken" (source also of Spanish portar), akin to porta "gate, portus "harbor" (from PIE *prto-, suffixed form of root *per- (2) "to lead, pass over"). The meaning "to carry (a rifle, etc.) in a military fashion" is from 1620s. Related: Ported; porting. The Latin verb is the source of many modern English words, including deport, export, import, report, support, important, and, ultimately, sports.
"the left side of a ship" (looking forward from the stern), 1540s, probably from the notion of "the side facing the harbor" (when a ship is docked); thus from port (n.1). On old-style vessels the steering oar was on the right side, thus they would tie up at a wharf on the other side. It replaced larboard in common usage to avoid confusion with starboard; officially so by Admiralty order of 1844 and U.S. Navy Department notice of 1846. As an adjective by 1857.
U. S. Navy Department, Washington, Feb. 18, 1846.
It having been repeatedly represented to the Department that confusion arises from the use of the words "larboard" and "starboard"' in consequence of their similarity of sound, the word "port" is hereafter to be substituted for "larboard." George Bancroft, Sec. of the Navy.
The whalemen are the only class of seamen who have not adopted the term port instead of larboard, except in working ship. The larboard boat was this boat to their great-grandfathers, and it is so with the present generation. More especially is this the case in the Atlantic and South Pacific fleets; but recently the term port-boat has come into use in the Arctic fleet. [Fisheries of U.S., V. ii. 243, 1887]