carboxyl

adj. containing the carboxyl group (Chemistry)

Carboxyl group or carboxy group -COOH or CO2H is a functional group present in amino acids and carboxylic acids. Its structure composed of one carbon atom attached to an oxygen atom by double bond and to a hydroxyl group by a single bond. It is often mentioned that a carboxyl group is a carbonyl group bonded to a hydroxyl group. The carboxyl group has one valence electron in its carbon atom, making it possible to be a part in a larger molecule by bonding through it.
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Carboxyl /car·box·yl/ the monovalent radical —COOH, occurring in those organic acids termed carboxylic acids. car·box·yl n. [more]Carboxyl - Community and Resources

Noun
1. the univalent radical -COOH; present in and characteristic of organic acids
(synonym) carboxyl group
(hypernym) group, radical, chemical group
Adjective
1. relating to or containing the carboxyl group or carboxyl radical
(synonym) carboxylic
(pertainym) carboxyl group
(classification) chemistry, chemical science

(n.)
The complex radical, CO.OH, regarded as the essential and characteristic constituent which all oxygen acids of carbon (as formic, acetic, benzoic acids, etc.) have in common; -- called also oxatyl.