|1.||a group of three; trio|
|2.||chem an atom, element, group, or ion that has a valency of three|
|3.||music a three-note chord consisting of a note and the third and fifth above it|
|4.||an aphoristic literary form used in medieval Welsh and Irish literature|
|5.||the US strategic nuclear force, consisting of intercontinental ballistic missiles, submarine-launched ballistic missiles, and bombers|
|[C16: from Late Latin trias, from Greek; related to Greek treis three]|
triad tri·ad (trī'ād', -əd)
A collection of three things or symptoms having something in common.
The transverse tubule, and the terminal cisternae on each side of it, in a skeletal muscle fiber.