The Collaborative International Dictionary
Polyacid
Polyacid \Pol`y*ac"id\, a. [Poly- + acid.] (Chem.) Capable of neutralizing, or of combining with, several molecules of a monobasic acid; having more than one hydrogen atom capable of being replaced by acid radicals; -- said of certain bases; as, calcium hydrate and glycerin are polyacid bases.
Wiktionary
polyacid
a. (context chemistry of a base English) polybasic n. (context chemistry English) Any polybasic acid