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noc·tur·nal

(nŏk-tûrnəl)

adj.

1. Of, relating to, or occurring in the night: nocturnal stillness.

2. Botany Opening at night. Used of flowers.

3. Zoology Most active at night: nocturnal lizards.

[Middle English, from Old French, from Late Latin nocturnālis, from Latin nocturnus, from nox, noct-, night; see nek^w-t- in the Appendix of Indo-European roots.]

noc·turnal·ly adv.

Indo-European & Semitic Roots Appendices

Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

Indo-European Roots

Semitic Roots

The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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