Porous means full of tiny holes that let liquid through. Porous rock, porous stone, a porous border.
In geology it decides where water and oil are stored, and a porous rock that also lets fluid move is called permeable — the two are different and constantly confused. Figuratively a porous border is one that leaks. Note pore; and that the Greek poros means a passage.
1adjectiveporousFull of tiny holes that let liquid through.
“The clay pot is porous, so water slowly seeps through it and keeps it cool.”
porous is a quality of holes.
Latin porus comes from Greek poros, a passage. Pore and emporium come from the same passage.
Proto-Indo-European
*per- (fare)
Latin
porus — an opening
Old French
poros
English, today
porous
From Old French poros, from Latin porus (“an opening”). by surface analysis, pore + -ous.
Etymology from Wiktionary, CC BY-SA