Wiktionary
n. (context fractional English) One of ninety-nine equal parts of a whole. num. (context ordinal English) The ordinal form of the number ninety-nine, describing a person or thing in position number 99 of a sequence.
Usage examples of "ninety-ninth".
One hundred eight West Ninety-ninth Street was a broad, prewar apartment house, unembarrassed by any distinguishing architecture, bright in the noonday sun.
I gathered the house specialized in new works by established playwrights, though there was the occasional old war-horse guaranteed to put butts in seats, and a few revivals of faded stars who'd only had the one hit, reprising the role for the ninety-ninth time.
I had my teaching certificate and a teacher's test score in the ninety-ninth percen-tile, but I learned that they weren't interested in having a real writer teach that subject.