I. |pälē+ noun
Etymology: International Scientific Vocabulary poly- + acid
1. : an acid (as phosphoric acid) having more than one acid hydrogen atom
2. : a complex acid of the group of isopoly or heteropoly acids
II. adjective
1. : able to react with more than one molecule of a monoacid to form a salt — used especially of bases
2. : having more than one hydrogen atom replaceable by basic atoms or radicals — used of acids and acid salts