- accretions1) N-COUNT An accretion is an addition to something, usually one that has been added over a period of time. [FORMAL]
...the mythical structure has been overlaid by literary accretions.2) N-UNCOUNT Accretion is the process of new layers or parts being added to something so that it increases in size. [FORMAL]
The larger the animal, the greater the accretion of poison in the fat.
English dictionary. 2008.