noun, plural: moieties
(general) A half or one of two approximately equal parts of something; an indefinite portion or part or share of the whole.
Recently, moiety is used synonymously for functional group, which may be erroneous. In the example above, each moiety of benzyl acetate contains a portion of the functional group. Hence, to use moiety to mean a functional group is, therefore, inaccurate in this case.
Moiety is originally a common term in anthropology and archeology to mean the half of a tribal family. An encounter between Elizabeth Bollwerk, an archeology graduate student, and a drug research scientist led to the term's crossover.