1. The cardinal number equal to 8 + 1.
2. The ninth in a set or sequence.
3. Something having nine parts, units, or members.
4. Games A playing card marked with nine pips.
5. A set of nine persons or things, especially:
a. Baseball The nine players on a side, or the whole team.
b. Nine Greek Mythology The nine Muses.
6. A size, as in clothing or shoes, designated as nine.
7. Sports The first or second 9 holes of an 18-hole golf course.
to the nines Informal
To the highest degree: dressed to the nines.
[Middle English, from Old English nigon; see new in the Appendix of Indo-European roots.]
nine adj. & pron.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 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.