Well, it is not Arabic only, "mañana" in Spanish means actually tomorrow, but often it is intended as "some time in the future", more like "soon" but also "not now and not so soon".

In Italian it is almost the same for "domani", with a lot of nuances depending on the context.

Only as an example, in Italian "Domani puoi sempre fare questo" which would translate literally to (and is probably perceived by a foreigner as) "Tomorrow you can always do this" actually means "In the future (indefinite, or "any time") you can still do this" (usually meaning reverting a present decision).