a combining form appearing in loanwords from French meaning “half” (demilune), “lesser” (demitasse), or sometimes used with a pejorative sense (demimonde); on this model, also prefixed to words of English origin (demigod).
Origin of demi-
< French, combining form representing demi (adj.; also noun and adv.) < Vulgar Latin *dīmedius, for Latin dīmidius half, equivalent to dī- di-2 + medius middle
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Word Origin for demi-
via French from Medieval Latin dīmedius, from Latin dīmīdius half, from dis- apart + medius middle
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