E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
or the pentad, the great mystic number, being the sum of 2 + 3, the first even and first odd compound. Unity is God alone, i.e. without creation. Two is diversity, and three (being 1 + 2) is the compound of unity and diversity, or the two principles in operation since creation, and representing all the powers of nature.