across vs. across from

[Ecoke0005]

which one is right?
can both be used? my dictionary says "across from" can be used, but not in British English, though.

To me, "from" is not necessary in a sentence, for example, "a house across from the store" because across is a preposition and "across" alone seems enough.

thank you.

[BrianL]

"Across from" and "across" have subtle differences.
For example, "the store across the street" works because one must physically cross over the street in order to get to the store. However, if talking about a house, you must use "from" in order to be understood. "The house across from the store" implies that there is something between the house and store that must be crossed. If you were to only say "the house across the store," it would sound like you had to walk through a store to get to the house.