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. • (Gradual) increase by an external addition of matter; (countable) an instance of this. • The process by which material is added to a geological feature; specifically, to a tectonic plate at a subduction zone. • Followed by of: external addition of matter to a thing which causes it to grow, especially in amount or size. • The process of separate particles aggregating or coalescing together; concretion; (countable) a thing formed in this manner. • 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. • Something gradually added to or growing on a thing externally. • A substance which has built up on the surface of an object, rather than become embedded in it. • Increase in property by the addition of other property to it (for example, gain of land by alluvion (“the deposition of sediment by a river or sea”) or dereliction (“recession of water from the usual watermark”), or entitlement to the products of the property such as interest on money); or by the property owner acquiring another person’s ownership rights; accession; (countable) an instance of this. • Increase of an inheritance to an heir or legatee due to the share of a co-heir or co-legatee being added to it, because the latter person is legally unable to inherit the share.