accretion

The act of increasing by natural growth; especially the increase of organic bodies by the internal accession of parts; organic growth.

The act of increasing, or the matter added, by an accession of parts externally; an extraneous addition.

Something added externally to promote the external growth of an item.

Concretion; coherence of separate particles.

(biology) A growing together of parts naturally separate, as of the fingers or toes.

(geology) The gradual increase of land by deposition of water-borne sediment.

(law) The adhering of property to something else, by which the owner of one thing becomes possessed of a right to another; generally, gain of land by the washing up of sand or sail from the sea or a river, or by a gradual recession of the water from the usual watermark.

(law) Gain to an heir or legatee; failure of a coheir to the same succession, or a co-legatee of the same thing, to take his share percentage.