Entry 1 sense Webster, 1913 Pyrogallic · Pyr·o·gal·lic · IPA 01 a. Pertaining to, derived from, or designating, an acid called pyrogallol. See Pyrogallol. 1. Pertaining to, derived from, or designating, an acid called pyrogallol. See Pyrogallol.(Chem.) See: Pyrogallol