An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

A group or set of three of one kind.
Optics: A compound lens made up of three elements that may or may not be cemented.

From trip-, from → triple + -et, from → doublet.

Setâyé, from setâ, → triple, + -(y)é nuance suffix.

The electronic state of an atom or molecule which has two unpaired electrons, and therefore whose total spin angular momentum is equal to 1.

→ triplet; → state.