Exosmose

Part of speech: noun, verb

Definitions

1. The movement of a liquid or gas outward through a semipermeable membrane, moving from a more concentrated solution toward a more dilute one
2. The passage of a fluid out through a selectively permeable barrier, driven by differences in concentration on either side of the membrane
3. Diffusion of solvent or dissolved substances outward across a membrane, a process important in biology and in certain filtration technologies

Etymology: Exosmose is a compound built from two Greek-derived parts. The first, "exo-", comes from the Greek "ex" ("out of"), which in turn descends from "éxō" ("outside"). The second, "osmosis", is a term from the same family of scientific coinages, so the word simply describes passage outward, the reverse of its better-known partner "endosmose", which describes passage inward. The core idea is that a fluid or gas moves through a membrane, traveling from the side where it is more concentrated toward the other side. The "exo-" prefix marks the direction: the flow leaves the enclosed space. Chemists and biologists use the pair together, so the outward and inward movements of the same process can be named in parallel. The archaic spelling "exosmose" follows the older English habit of ending such nouns and verbs in "-ose", while "exosmosis" keeps the "-osis" ending of the process noun. Both forms are used for the same meaning.

Antonyms: endosmose