"Hol van a mosdó?"

Translation: Where is the restroom?

[MaerskBuddhapest]

Shouldn't "bathroom" and "restroom" be also accepted?

[vvsey]

Yes

[deactivated user]

In England we don't usually talk about restrooms, and bathroom usually means a place where you have a bath - it may or may not have a lavatory.

[Chris265302]

Lavatory is commonly used in UK & Ireland for bathroom/toilet

[weitzhandler]

Where is the sink?

[chirelchirel]

Is there a parallel form with -szoba?

[RyagonIV]

There's fürdőszoba, which is the actual bathroom with shower and/or tub and all. But no, mosdó is on its own. You could say mosdószoba, but it's pretty redundant.