Adsorption

Part of speech: noun

Definitions

1. The mechanism in which substances attach to a surface without penetrating it includes the gathering of molecules at a boundary between two phases
2. The process involves the adhesion of particles onto a surface, whereby molecules cluster at the interface of different phases without becoming integrated
3. The process where molecules accumulate and stick to the surface of a solid or liquid without entering its bulk

Etymology: The key to "adsorption" is the difference between two prefixes that look nearly identical on the page. Its root is "absorption", which comes from the Latin "absorbere", to suck up or swallow, and the "ab-" there means "away" or "into" the interior of something. Adsorption swaps that prefix for "ad-", meaning "to" or "toward", so the sense shifts from a substance being drawn inside a body to a substance clinging to the outside of one. English took the word from German, where "Adsorption" was formed the same way, with "ad-" attached to "Absorption". The German chemists who used it needed a term for surface accumulation that could be told apart from true absorption, and the new coinage did exactly that. The word therefore reads as a deliberate contrast: one prefix keeps the substance inside, the other keeps it on the surface.

Synonyms: adherence, attachment