ENGLISH
REFERENCE

doublet

n.
UK //dˈʌblət// dou·blet
  1. 1 linguistic cognates (n.)
    C2 Proficiency Technical Academic Linguistics

    two different words in the same language that come from the same original word.

    one of two or more words in a language that share a common etymological ancestor but have diverged in form and meaning.

    Example

    'Shirt' and 'skirt' are a doublet because they both come from the same old word.

    Example

    The English language is rich in etymological doublets, such as 'fragile' and 'frail', which entered the lexicon via different routes from the same Latin root.
  2. 2 historical clothing (n.)
    C2 Proficiency Archaic Literary

    a short, tight jacket worn by men in Europe between the 1400s and 1600s.

    a man's close-fitting, padded jacket, often with detachable sleeves, characteristic of European fashion from the late Middle Ages to the mid-17th century.

    Example

    The actor wore a velvet doublet for his role in the Shakespeare play.

    Example

    The museum's textile collection includes a rare silk doublet from the Elizabethan era, remarkably preserved with its original silver embroidery.
  3. 3 imitation gemstone (n.)
    C2 Proficiency Technical

    a fake jewel made by joining two pieces of glass or stone together.

    a counterfeit or assembled gemstone consisting of two layers, typically a thin slice of genuine stone glued to a glass or synthetic base.

    Example

    The ring looked like a real emerald, but it was actually a clever doublet.

    Example

    Jewellers must be careful to distinguish between solid opals and doublets, as the latter are significantly less valuable due to their composite nature.
  4. 4 optical lenses (n.)
    C2 Proficiency Technical Science

    a pair of lenses used together in a microscope or camera to make the image clearer.

    an arrangement of two lenses, often made of different types of glass, designed to reduce optical errors like chromatic aberration.

    Example

    The microscope uses a doublet to help the scientist see the tiny cells clearly.

    Example

    By using an achromatic doublet, the telescope designer was able to eliminate the purple fringing that often plagues cheaper optical systems.

Etymology 1

From Middle English doublet, a borrowing from Old French doublet, from double, duble, doble + -et.

Etymology 2

From Italian giubbetta, from giubba, from Arabic جبة (“to en-wrap”).

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Related words

Last updated July 31, 2026