a. [ Hexa- + basic. ] (Chem.) Having six hydrogen atoms or six radicals capable of being replaced or saturated by bases; -- said of acids; as, mellitic acid is hexabasic. [ 1913 Webster ]

a. [ Penta- + basic. ] (Chem.) Capable of uniting with five molecules of a monacid base; having five acid hydrogen atoms capable of substitution by a basic radical; -- said of certain acids. [ 1913 Webster ]

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 ]