The Collaborative International Dictionary
Tetrabasic
Tetrabasic \Tet`ra*bas"ic\, a. [Tetra- + basic.] (Chem.) Capable of neutralizing four molecules of a monacid base; having four hydrogen atoms capable of replacement by bases; quadribasic; -- said of certain acids; thus, normal silicic acid, Si(OH)4, is a tetrabasic acid.
Wiktionary
tetrabasic
a. 1 (context chemistry of an acid English) containing four replaceable hydrogen atoms 2 (context chemistry of a salt English) having four atoms of a univalent metal