(~s)
1.
An ~ is an addition to something, usually one that has been added over a period of time. (FORMAL)
The script has been gathering editorial ~s for years.
N-COUNT
2.
Accretion is the process of new layers or parts being added to something so that it increases in size. (FORMAL)
A coral reef is built by the ~ of tiny, identical organisms.
N-UNCOUNT