In mathematics, a transcendental number is any complex number that is not algebraic, i.e. it is not a root of any polynomial whose coefficients are integers, or, equivalently, it is not a root of any polynomial whose coefficients are rational.
Transcendental numbers are necessarily irrational, but there are many irrational numbers that are not transcendental. For instance, is irrational. However it is algebraic, since it is a root of the polynomial . It is thus irrational but not transcendental.