Of an acid: Having the property of exchanging three atoms of hydrogen for three of potassium or sodium, and thus forming a salt; e.g. phosphoric…

Of an acid: having one replaceable hydrogen atom. Also: having one base, or one atom of a base. Formerly also: †monovalent (obsolete).

Of an acid: Containing four atoms of hydrogen replaceable by more electropositive elements or radicals. Of a salt: Derived from such an acid.

Of an acid: capable of donating more than one proton to a base; polybasic. Also occasionally: (of a base) capable of accepting more than one…