pentacid

Century Dictionary and Cyclopedia

1. Noting a base containing five combining units of the radical hydroxyl, HO, or one equivalent to a pentabasic acid, molecule for molecule.

Wiktionary

1. adj. chemistry Capable of neutralizing, or combining with, five molecules of a monobasic acid; having five hydrogen atoms capable of substitution by acid residues; said of certain complex bases.

GNU Webster's 1913

1. adj. (Chem.) Capable of neutralizing, or combining with, five molecules of a monobasic acid; having five hydrogen atoms capable of substitution by acid residues; -- said of certain complex bases.