Each of the 45 circles is denoted by an unordered pair of duads.
The duad has been generated from the monad, according to Pythagoras.
Whether the root be a perfect monosyllable, or a duad, or even triad, formed on the monosyllable, it is the same thing with respect to the origin of the root.
The figures of the duad are the Son, who is the splendor of the Father, and the Word, which is the form of thought.
Synonyms
two, couple, duo, duology, brace, twosome
Origin
Mid 17th century: from Greek duas, duad- 'two', probably influenced by Latin duo.