Word forms: accretions
COBUILD Advanced British English Dictionary1. countable nounAn accretion is an addition to something, usually one that has been added over a period of time. [formal] ⇒ The script has been gathering editorial accretions for years.2. uncount nounAccretion is the process of new layers or parts being added to something so that it increases in size. [formal] [+ of] ⇒ A coral reef is built by the accretion of tiny, identical organisms.