Ninetieth

Part of speech: adjective, noun

Definitions

1. Relating to the ordinal position of ninety in a sequence or list
2. Describing something that comes after the eighty-ninth in rank or order
3. Pertaining to the one associated with the number ninety in count or sequence

Etymology: "Ninetieth" is an ordinal built by adding the suffix "-th" to "ninety," the same pattern used for the other tens. Its older form was "ninteth," which came from Middle English "nyntithe." Over time the spelling and sound shifted to the familiar modern form, with the "-ie-" of "ninety" giving way to a stressed "-ie-" in the ordinal, a change that also shaped its neighbour "twentieth." Because the word is simply a regular formation on the cardinal "ninety," its meaning is straightforward: the item in position ninety in a sequence, or one of ninety equal parts. The ending is the same "-th" that marks "fourth," "tenth," and "hundredth," so once you know the cardinal number, the ordinal follows the established pattern.

Synonyms: 90th, ninetieth