Meaning

noun position nine in a countable series of things

noun one part in nine equal parts

adjective coming next after the eighth and just before the tenth in position

originFrom Middle English nynthe, nynte, from Old English niġoþa, from Proto-Germanic *newundô; the -n- was reinserted by analogy with nine. Equivalent to nine + -th (ordinal suffix).

Etymology from Wiktionary, CC BY-SA 3.0