accretion

1. Increase by natural growth, especially the gradual increase of organic bodies by the internal addition of matter; organic growth; also, the amount of such growth. (figuratively, uncountable)
2. (Gradual) increase by an external addition of matter; (countable) an instance of this. (uncountable) · Near-synonym: accumulation· A mineral augments not by growth, but by accretion.
3. The process by which material is added to a geological feature; specifically, to a tectonic plate at a subduction zone. (countable, uncountable)
4. Followed by of: external addition of matter to a thing which causes it to grow, especially in amount or size. (figuratively, uncountable)
5. The process of separate particles aggregating or coalescing together; concretion; (countable) a thing formed in this manner. (uncountable) · The accretion of particles forms a solid mass.
6. The formation of planets, stars, and other celestial bodies by the aggregating of matter drawn together by gravity; also, the growth of a celestial body through this process. (countable, uncountable)
7. Something gradually added to or growing on a thing externally. (countable, figuratively) · accretion of ice
8. A substance which has built up on the surface of an object, rather than become embedded in it. (countable, figuratively, uncountable)

Plural accretions