porous adj.

late 14c., "minute opening, small orifice, or perforation" in the earth, a tree, the body of a human, animal, or insect, a bone, etc.," from Old French pore (14c.) and directly from Latin porus "a pore," from Greek poros "a pore," literally "passage, way," from PIE *poro- "passage, journey," suffixed form of PIE root *per- (2) "to lead, pass over."