nine · number /naɪn/Full view
nine
A1 the number 9
Dictionary examples:

a nine-month prison sentence

The birthday girl was wearing a badge with a nine on it.

Learner example:

I start college at half past nine. (Skills for Life (Entry 1); A1; Romanian)

be on cloud nine
C2 to be extremely happy and excited
Dictionary example:

After I heard I'd got the job, I was on cloud nine!

Learner example:

But now, after the promise in which both said "yes", she was on cloud nine. (Certificate of Proficiency in English; C2; German)

Cambridge logo