fractions

I. fifth¹ /fɪfθ/ BrE AmE adjective
[Language: Old English; Origin: fifta, from fif 'five']
1. coming after four other things in a series:
in the fifth century
her fifth birthday
2. fifth wheel American English informal someone who is not wanted in a particular group of people:
They’d made her feel like a fifth wheel.
—fifth pronoun:
I’m planning to leave on the fifth (=the fifth day of the month).
—fifthly adverb

Oxford Advanced Learner's Dictionary

fifth

fifth [fifth fifths] ordinal number, noun [fɪfθ] [fɪfθ]

ordinal number
5th
• Today is the fifth (of May).
• the fifth century BC
• It's her fifth birthday.
• My office is on the fifth floor.
• It's the fifth time that I've been to America.
• Her mother had just given birth to another child, her fifth.
• the world's fifth-largest oil exporter
• He finished fifth in the race.
• Edward V (= Edward the Fifth)

Idiom: take the fifth

noun
each of five equal parts of sth
• She cut the cake into fifths.

• He gave her a fifth of the total amount.

Cambridge Advanced Learner's Dictionary

Cambridge Advanced Learner's Dictionary - 4th Edition

fifth / fɪfθ / ordinal number

A2 5th written as a word:

the fifth floor of the building

Tomorrow is the fifth ( of September).

I was/came fifth in the race.

Collins COBUILD Advanced Learner’s English Dictionary

fifth

[fɪ̱fθ]
♦♦
fifths
1) ORD The fifth item in a series is the one that you count as number five.
Joe has recently returned from his fifth trip to Australia.
2) FRACTION A fifth is one of five equal parts of something.
India spends over a fifth of its budget on defence.

Merriam-Webster's Advanced Learner's Dictionary

Merriam-Webster's Advanced Learner's Dictionary:

fifth

²fifth adj : occupying the number five position in a series
• the fifth dancer in the line
• the fifth annual awards banquet
- fifth adv
• the nation's fifth largest city
• She finished fifth in the race.