Chem. [f. TRI- 5 + Gr. ὔδωρ water + -IC.] Containing three hydroxyl groups, OH; thus glycerin or glycerol, C3H5(OH)3, is a trihydric alcohol; pyrogallic acid or pyrogallol, C6H3(OH)3, is a trihydric phenol.
1866. Frankland, Lect. Notes, 269. Relations of Glycerin to the Trihydric Acids, Glyceric Acid,… and Tartronic Acid.
1881. Frankland & Japp, Lect. Notes (ed. 3), II. 105. Trihydric Alcohols. Glycerin … series. These alcohols contain three semimolecules of hydroxyl.
1900. Smith, Richter’s Org. Chem. (ed. 3), II. 140. The phenols, like the alcohols, are distinguished as mono-, di-, and trihydric, according to the number of hydroxyl groups which have entered.
