[determiner], [pronoun], [adjective], [adverb] [not gradable], nounThat's the fiftieth Christmas card I've written.She was the fiftieth of the applicants we interviewed.He is/is ranked fiftieth in the world.A fiftieth is one of fifty equal parts of something.
FIFTIETH
Meaning of FIFTIETH in English
Cambridge English vocab. Кембриджский английский словарь. 2012