The Collaborative International Dictionary
carboxyl group \car*box"yl group`\ (k[aum]r*b[o^]ks"[i^]l gr[=oo]p), n. (Chem.) a monovalent organic radical (written -COOH, -CO2H or -CO.OH) whose presence confers acidic properties on the compound containing it; -- called also carboxylic group. Monocarboxylic acids (such as acetic acid or butyric acid) have one carboxyl group, dicarboxylic acids (such as oxalic acid or malonic acid) have two, tricarboxylic acids (such as citric acid) have three. It is weakly acidic, the pKa of acetic acid being 4.75.
WordNet
n. the univalent radical -COOH; present in and characteristic of organic acids [syn: carboxyl]
Usage examples of "carboxyl group".
One example of these, a compound with a molecule composed of a chain of 12 carbon atoms, with a carboxyl group (-COOH) at each end and a double bond between carbon-2 and carbon-3, is called traumatic acid (troh-mafik.
Actually, THC acid and the other necessary cannabinoid acids are not psychoactive until they decarboxylate (lose an acidic carboxyl group [COOHI).