Meaning

noun (biology, chemistry) diffusion of molecules through a semipermeable membrane from a place of higher concentration to a place of lower concentration until the concentration on both sides is equal

originFrom endosmose and exosmose, both coined by French physician Henri Dutrochet in 1826; from (respectively) Ancient Greek ἔνδον (éndon, “within”) and Ancient Greek ἔξω (éxō, “outer, external”), plus Ancient Greek ὠσμός (ōsmós, “push, impulsion”), from ὠθέω (ōthéō).

Etymology from Wiktionary, CC BY-SA 3.0