On is a phrasal verb meaning "don't hang up" or "wait a moment". It is used in spoken English. hang

On is also a phrasal verb, meaning "wait a minute", but it is generally not used in telephone language. These two phrasal verbs are intransitive verbs and generally have no object, such as:

can

you

hang

exist

for

a

Minutes?

please

keep

Open.

I

will

let go

you

Go through.

I hope it can help you solve the problem.