Wiktionary
n. (context mathematics English) any irrational number that is not an algebraic number
WordNet
n. an irrational number that is not algebraic
Wikipedia
In mathematics, a transcendental number is a real or complex number that is not algebraic—that is, it is not a root of a non-zero polynomial equation with integer (or, equivalently, rational) coefficients. The best-known transcendental numbers are π and e. Though only a few classes of transcendental numbers are known (in part because it can be extremely difficult to show that a given number is transcendental), transcendental numbers are not rare. Indeed, almost all real and complex numbers are transcendental, since the algebraic numbers are countable while the sets of real and complex numbers are both uncountable. All real transcendental numbers are irrational, since all rational numbers are algebraic. The converse is not true: not all irrational numbers are transcendental; e.g., the square root of 2 is irrational but not a transcendental number, since it is a solution of the polynomial equation . Another algebraic number irrational (that is not a rational number, despite being a ratio) but not a transcendental is φ or ϕ the golden ratio.
Usage examples of "transcendental number".
This great serpent, this incalculable dragon, was pi, a transcendental number, yielding, when expressed in decimal notation, an infinite table of random numbers.