cuivre.

Inherited from Old French cuivre, quivre, queivre, coivre, from Latin Cyprium, cupreum (aes) (compare cuprum) from Ancient Greek Κῠ́προς (Kŭ́pros, “Cyprus”). It was not uncommon for Greek short ῠ (pronounced in Classical Attic as /y/) to be adapted as Latin short ŭ. This would normally yield Proto-Western-Romance *[o], but a following palatal sound apparently could cause *[o] to be raised to *[u] (or alternatively, the original close quality of Latin short ŭ to be retained) early enough for the sound change of Proto-Western-Romance *[u] > Old French [y] to apply, yielding the now standard form with ⟨ui⟩ (Old French [yj], modern French [ɥi]). Compare truite from Late Latin tructa, puits from Latin puteus, and huis from Latin ōstium. (But ⟨oi⟩ is seen in forms such as rasoir < rasōrium). Compare the development of ēbrius to French ivre (as opposed to *oivre). A competing explanation supposes a sporadic lowering of Latin ŭ to ŏ (yielding *coprium) or of Western Romance *o to *ɔ, since *ɔ was regularly diphthongized to *uɔ before a palatal and the resulting triphthong *uɔi was simplified to Old French ui (compare corium > cuir).

Inherited from Old French cuivre, quivre, queivre, coivre, from Latin Cyprium, cupreum (aes) (compare cuprum) from Ancient Greek Κῠ́προς (Kŭ́pros, “Cyprus”). It was not uncommon for Greek short ῠ (pronounced in Classical Attic as /y/) to be adapted as Latin short ŭ. This would normally yield Proto-Western-Romance *[o], but a following palatal sound apparently could cause *[o] to be raised to *[u] (or alternatively, the original close quality of Latin short ŭ to be retained) early enough for the sound change of Proto-Western-Romance *[u] > Old French [y] to apply, yielding the now standard form with ⟨ui⟩ (Old French [yj], modern French [ɥi]). Compare truite from Late Latin tructa, puits from Latin puteus, and huis from Latin ōstium. (But ⟨oi⟩ is seen in forms such as rasoir < rasōrium). Compare the development of ēbrius to French ivre (as opposed to *oivre). A competing explanation supposes a sporadic lowering of Latin ŭ to ŏ (yielding *coprium) or of Western Romance *o to *ɔ, since *ɔ was regularly diphthongized to *uɔ before a palatal and the resulting triphthong *uɔi was simplified to Old French ui (compare corium > cuir).