accretion

Learned borrowing from Latin accrētiō (“increase, increment”) + English -ion (suffix forming nouns denoting actions or processes, or their results). Accrētiō is derived from accrēscō (“to grow, increase”) +‎ -tiō (suffix forming nouns denoting actions or processes, or their results); and accrēscō is from ac- (a variant of ad-, prefix meaning ‘to’, or having an intensifying effect) +‎ crēscō (“to grow; to increase”) (ultimately from Proto-Indo-European *ḱer- (“to cause to grow; to grow; to nourish”)).

Doublet of accrue, crescent, and increase.