The number four; a collection of four things.
The number four; a collection of four things; a quaternion.
A tetravalent or quadrivalent atom or radical; as, carbon is a tetrad.
TET'RAD, noun [Gr. the number four.] The number four; a collection of four things.
1. To hasten; to quicken; to accelerate motion or progress. The general sent orders to expedite the march of the army. Artificial heat may expedite the growth of plants.
2. To dispatch; to send from.
Such charters are expedited of course.
3. To hasten by rendering easy.
2. Active; nimble; ready; prompt.