seventh

I. sev‧enth¹ /ˈsevənθ/ BrE AmE adjective
1. coming after six other things in a series:
in the seventh century
her seventh birthday
2. be in seventh heaven informal to be extremely happy
—seventh pronoun:
I’m planning to leave on the seventh (=the seventh day of the month).

Oxford Advanced Learner's Dictionary

seventh

sev·enth [seventh sevenths] ordinal number, noun [ˈsevnθ] [ˈsevnθ]

ordinal number
7th There are examples of how to use ordinal numbers at the entry for fifth.

Idiom: in seventh heaven

noun

each of seven equal parts of sth

Cambridge Advanced Learner's Dictionary

Cambridge Advanced Learner's Dictionary - 4th Edition

seventh / ˈsev. ə nθ / ordinal number

A2 7th written as a word:

It's the seventh ( of May) today.

Our team was/came seventh.

Collins COBUILD Advanced Learner’s English Dictionary

seventh

[se̱v(ə)nθ]
♦♦
sevenths
1) ORD The seventh item in a series is the one that you count as number seven.
I was the seventh child in the family. There were 11 of us altogether.
2) FRACTION A seventh is one of seven equal parts of something.
A million people died, a seventh of the population.

Merriam-Webster's Advanced Learner's Dictionary

Merriam-Webster's Advanced Learner's Dictionary:

seventh

²seventh adj : occupying the number seven position in a series
• on the seventh day
• the book's seventh edition
• her seventh goal of the season
• I finished in seventh place in the competition.
- seventh adv
• She finished seventh in the race.
• the nation's seventh largest city