ninth (adj., n.)

"next in order or rank after the eighth; being one of nine equal parts into which a whole is regarded as divided;" c. 1300, nynþe, an alteration or replacement (by influence of nine) of nigonðe, from Old English nigoða, nigende, for which compare seventh. Also see -th (1). As a noun, "ordinal numeral corresponding to nine," late 13c. As the name of a musical interval, 1590s. Related: Ninthly.

updated on July 04, 2022

Definitions of ninth from WordNet
ninth (n.)
position nine in a countable series of things;
going into the ninth they were a run ahead
ninth (n.)
one part in nine equal parts;
Synonyms: one-ninth
ninth (adj.)
coming next after the eighth and just before the tenth in position;
Synonyms: th
Etymologies are not definitions. From, not affiliated with etymonline.