09-27-2021-2120 - moiety

 In organic chemistry, a moiety (/ˈmɔɪəti/) is a part of a molecule^[1][2] that is given a name because it is identified as a part of other molecules as well. 

Typically, the term is used to describe the larger and characteristic parts of organic molecules, and it should not be used to describe or name smaller functional groups ^[1][2] of atoms that chemically react in similar ways in most molecules that contain them.^[3] Occasionally, a moiety may contain smaller moieties and functional groups. 

A moiety that acts as a branch extending from the backbone of a hydrocarbon molecule is called substituent or side chain, which typically can be removed from the molecule and substituted with others.

Benzyl acetate contains a benzyloxy moiety (encircled with light orange). It also contains an ester functional group (in red), and an acetyl functional group (encircled with dark green). Other divisions can be made.

https://en.wikipedia.org/wiki/Moiety_(chemistry)

Moiety conservation is the conservation of a subgroup in a chemical species, which is cyclically transferred from one molecule to another.

https://en.wikipedia.org/wiki/Moiety_conservation