fifth | meaning of fifth in Longman Dictionary of Contemporary English | LDOCE

From Longman Dictionary of Contemporary Englishfifthfifth1 /fɪfθ/ ●●● S3 W3 adjective    1 coming after four other things in a series  in the fifth century  her fifth birthday2 → fifth wheel —fifth pronoun  I’m planning to leave on the fifth (=the fifth day of the month). —fifthly adverbExamples from the Corpusfifth• We came in fifth place in the race.the fifth• Her party is on the fifth.Numbersfifthfifth2 noun [countable]    1 HMNone of five equal parts of something2 American EnglishDFD an amount of alcohol equal to 1/5 of an American gallon(1), sold in bottles  a fifth of bourbonOrigin fifth1 Old English fifta, from fif “five”