besides, beside

As prepositions, these two are commonly interchanged, but their meanings do differ, according to traditionalists.

Besides means “other than” or “in addition to” while beside means “next to.”

If you say there is no one beside you on the bus, then the nearest seats are empty. If you say there is no one besides you on the bus, then either you drive the bus or you’re about to crash.

But many writers ignore this distinction. It is true that besides can never mean “at the side of,” but many writers use beside in place of besides.

Watch out for ambiguity, however. If you say there was no one beside you at the dinner table, that could mean either that the chairs next to you were empty (beside) or that you dined alone (besides).

The word besides also acts as an adverb. It means “furthermore” or “in addition.”

Example: It was obvious that I was the only married man in the group when I realized that everyone besides me wanted to sit beside her.