Monomial Surd
A surd consisting of only one term is called monomial surd.
Binomial Surd
An expression consisting of the sum or difference of two monomial surds or the sum of a monomial surd and a rational number is called a binomial surd.
Example:
Conjugate Surds
Two binomial surds which differ only in sign (+ or -) between the terms connecting them are called conjugate surds.
The simplest rationalizing factor of a binomial surd is its conjugate as