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."

"inclined to doubt," c. 1600, from French aporetique, from Greek aporetikos, from aporeein "to be at a loss, be without means or resources," from aporos "impassable, impracticable, very difficult; hard to deal with; at a loss," from a- "not, without" (see a- (3)) + poros "passage" (see pore (n.)).

a Latin error for bosporus, from Greek bosporos, a name applied to several channels or straits between seas, literally "ox's ford," from bous "ox" (from PIE root *gwou- "ox, bull, cow") + poros "passage, ford" (see pore (n.)). It was especially the name of the strait between the Sea of Marmora and the Black Sea (the Thracian Bosphorus).

"morbid absorption of bone, so that it becomes abnormally porous," 1846, from osteo- "bone" + Greek poros "passage; pore; voyage" (see pore (n.)) + -osis. Related: Osteoporotic.

"the sponges," as an animal division or class, 1843, Modern Latin, literally "bearing pores," neuter plural of porifer, from Latin porus "pore, opening" (see pore (n.)) + -fer "bearing" (from PIE root *bher- (1) "to carry"). So called for the numerous pores which perforate the body-wall. Related: Poriferal; poriferous.

"bearing or having pores," 1834, from Latin porus "pore, opening" (see pore (n.)) + -ferous "producing, containing," from Latin ferre "to bear, carry" (from PIE root *bher- (1) "to carry").

"state or quality of containing pores," late 14c., porosite, from Old French porosité, from Medieval Latin porositas (13c.), from Latin porus (see pore (n.)).

late 14c., "full of pores, permeable by means of having small perforations," from Old French poros (14c., Modern French poreux) and directly from Medieval Latin porosus; or directly from Latin porus "an opening" (see pore (n.)). Figurative use from 1640s.