portal (n.)

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.

Proto-Indo-European root meaning "to lead, pass over." A verbal root associated with *per- (1), which forms prepositions and preverbs with the basic meaning "forward, through; in front of, before," etc.

It forms all or part of: aporia; asportation; comport; deport; disport; emporium; Euphrates; export; fare; farewell; fartlek; Ferdinand; fere; fern; ferry; firth; fjord; ford; Fuhrer; gaberdine; import; important; importune; opportune; opportunity; passport; porch; pore (n.) "minute opening;" port (n.1) "harbor;" port (n.2) "gateway, entrance;" port (n.3) "bearing, mien;" port (v.) "to carry;" portable; portage; portal; portcullis; porter (n.1) "person who carries;" porter (n.2) "doorkeeper, janitor;" portfolio; portico; portiere; purport; practical; rapport; report; sport; support; transport; warfare; wayfarer; welfare.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit parayati "carries over;" Greek poros "journey, passage, way," peirein "to pierce, pass through, run through;" Latin portare "to carry," porta "gate, door," portus "port, harbor," originally "entrance, passage," peritus "experienced;" Avestan peretush "passage, ford, bridge;" Armenian hordan "go forward;" Old Welsh rit, Welsh rhyd "ford;" Old Church Slavonic pariti "to fly;" Old English faran "to go, journey," Old Norse fjörðr "inlet, estuary."