a. Twelve o'clock in the daytime; midday.
b. The time or point in the sun's path at which the sun is on the local meridian. Also called noontide, noontime.
2. The highest point; the zenith.
3. Archaic Midnight.
[Middle English non, from Old English nōn, canonical hour of nones (3 PM in early Middle Ages), from Late Latin nōna (hōra), ninth (hour after sunrise), nones, feminine sing. of Latin nōnus, ninth; see new in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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:
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.