Etymology: Late Latin dyad-, dyas, from Greek, from dyo

The word dyad' has a number of uses:

• A dyad (general) pair, consisting of two parts.
• A dyad (music) is any two notes or pitches
• A dyad (sociology) is a group of two people
• A dyad (biology) is a pair of chromosomes during meiosis
• Dyadic (used mainly in mathematics)

Dyade