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clarification on usage of across and beside - WordReference Forums
If A is beside B, we can also say 'A and B are side by side', because the side of A is next to the side of B. In the case of a street, if they are side by side, they must be on the same side of the street, and there must be nothing, except perhaps a small gap, between them. In other words, the buildings are adjacent. On the other hand, if they are across the street from each other, then their ...