Grammatical role of можно

Question

I have learned how to translate "можно" in phrases (e.g. with "it is possible", "one can", "it can be (done)").

However, I would like to know the actual grammatical role of the word.

My conjecture is the following:

It is an adjective singular neutrum that simply means "possible", but which is no longer used outside this kind of phrase, but still exists in composite adjectives like возмо́жный.

I would like to know if this is right and if it indeed comes from an older adjective no longer in common use.

Answer 1

It's predicative. equal to возможно

It's really hard to explain fully but will try to clarify some things

you can say мне можно -> I may

but

you can't say мне возможно but это для меня возможно - it is possible for me

In questions можно means may like a question to action...

можно мне .... -> May I ....

And возможно-ли что ... will strongly still be is it possible that ...

in nutshell можно and возможно have got the same base мож and same suffix but used in different ways...

как можно скорее - as soon as possible

возможно земля круглая - maybe the earth is round