1 The act of increasing by natural growth; esp. the increase of organic bodies by the internal accession of parts; organic growth. Arbuthnot.
2 The act of increasing, or the matter added, by an accession of parts externally; an extraneous addition; as, an accretion of earth. A mineral . . . augments not by grown, but by accretion. Owen. To strip off all the subordinate parts of his as a later accretion. Sir G. C. Lewis.
3 Concretion; coherence of separate particles; as, the accretion of particles so as to form a solid mass.
4 A growing together of parts naturally separate, as of the fingers toes. Dana.