OX-

I. combining form

or oxo-

Etymology: French, from oxygène oxygen — more at oxygen

1. : containing oxygen — especially in the names of various cyclic compounds

ox azole

2. usually oxo- : containing oxygen in a carbonyl group specifically regarded as formed by replacement of two hydrogen atoms in a methylene group by oxygen — in names of ketones or compounds (as heterocyclic compounds) that are not true ketones because the carbonyl group is not attached to two carbon atoms

oxo -acetic acid

2- oxo -indoline

ox indole

— distinguished from oxy- ; compare ket-

II. combining form

Etymology: by shortening

: oxal-

ox amide