the act of increasing by natural growth; esp. 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; as, an accretion of earth.-concretion; coherence of separate particles; as, the accretion of particles so as to form a solid mass.-a growing together of parts naturally separate, as of the fingers toes.-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.-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.