across from / opposite
How to name a position on the other side of a street, table, or room.
Use across from when one thing faces another with space between: the shop across from the courthouse, she sat across from me. Use opposite freely as an adjective (the opposite wall, opposite sides). As a preposition meaning “facing,” opposite the bank is readable but less usual than across from the bank. Do not use across from opposite or opposite from for the same idea.
Examples
UseThe café sits across from the library.
UseThey took seats on opposite sides of the table.
PreferShe sat across from the witness.
AvoidShe sat opposite from the witness.
Opposite as a bare preposition (opposite the station) is common in British prose. It is not wrong here; across from is the default facing phrase.