A carboxylic acid is an organic compound that contains a carboxyl functional group (-COOH), consisting of a carbon atom double-bonded to an oxygen atom and also bonded to a hydroxyl group (-OH). This functional group is what gives carboxylic acids their acidic properties, allowing them to donate protons (H+) in a solution. Carboxylic acids are pivotal in organic chemistry and are closely related to aldehydes and ketones, as they can be derived from these compounds through oxidation processes.