aceto-

1. a combining form with the meanings “vinegar,” “acetic acid,” used in the formation of compound words (acetometer), especially in the names of chemical compounds in which acetic acid or the acetyl group is present (acetophenetidin).

combining form

1. containing an acetyl group or derived from acetic acidacetone

before vowels acet-, word-forming element from comb. form of acetic and generally indicating compounds from or related to acetic acid.

pref.

1. Acetic acid:acetaldehyde.
2. Acetyl:acetanilide.