doublet

noun

• 1either of a pair of similar things, in particular.
• either of two words of the same historical source, but with two different stages of entry into the language and different resultant meanings, for example fashion and faction, cloak and clock.
• (doublets) the same number on two dice thrown at once.
• Physics & Chemistry a pair of associated lines close together in a spectrum or electrophoretic gel.
• a combination of two simple lenses.

• 2a man’s short close-fitting padded jacket, commonly worn from the 14th to the 17th century.