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.
[1913 Webster]