Question

what is polybasic acid ??

Answer 1

 two or more basic groups is called polybasic acid.
it contains two or more replaceable hydrogen atoms. 

Answer 2

Adjective. (comparative more polybasic, superlative most polybasic) (chemistry, of an acid) containing two or more replaceable hydrogen atoms. (chemistry, of a salt) having two or more atoms of a univalent metal. (chemistry, of a base) Having two or more basic groups; see also polybase.