When it is a hall of a hotel or public building, it is the same word - 'hall' but it is pronounced differently, without the 'h' being pronounced.A reception hall is "'hall d'acceuil" An entry hall of...
If you mean lower : en bas or plus bas (further down), en contrebas (for sloping places - mountains ..)
To look down - regarder en bas
If you mean further south, it is au sud or plus au sud
If you...