Accretion

Accretion-n
1-an increase in size or amount as a result of something accumulating or being added gradually, or something accumulated in this way
2-something added to something else, for example, a fund or account, from an external source
3-a process in which matter revolving around an astronomical object is gradually pulled in and added to the body's mass
4-a process by which a body of rock or a landmass increases in size as a result of material accumulating on or around it
5-a process by which the size of a continent increases as a result of the moving together and deforming of tectonic plates

Synonyms
accumulation
buildup
accrual
increase
anlargement
addition
growth
erosion (antonym)