idioms

[ngongrom]

I know the meaning of the idiom "on cloud nine". It means you are in happy spirit but I can't understand why people use the number "nine" not another numbers. please help me

[Tdol]

I heard that it is the highest layer of cloud, so it's the top, the peak. 'On cloud seven' is an alternative form, though much less common.

[nyggus]

Hey tdol, maybe this 'on cloud seven' comes from Polish? To say 'to be on could nine' we use 'to be in seventh heaven.'

Best

[Tdol]

We have 'seventh heaven' in English too- an example of a transnational idiom.