1. at side of: in a position next to or alongside
e.g. Sit beside me.
2. compared with: in comparison with
e.g. handsome beside his brother
3. as well as: in addition to
e.g. in another dictionary beside this one
1. moreover: what is more
e.g. He’s my cousin. Besides, he’s good company.
2. too: as well or in addition
I’ve paid for his education and plenty more besides!
as well: in addition to somebody or something specified or understood
e.g. Besides fruit, we’ll also need cheese and crackers.
BESIDE vs BESIDES
Beside is a preposition referring to physical position: Come and sit beside me. It is also used to mean “in addition to,” although this can lead to confusion with the meaning “at the side of.” Besides is an adverb meaning “what is more” or “in addition”: It’s late, and besides, the weather’s too cold.; I’ve money to live on, and plenty more besides. It is also a preposition meaning “in addition to”: There are other people involved besides us. Note that besides is inclusive, whereas except is exclusive, so that Besides Larry, we’ll invite John, Jake, and Renée means that Larry is also invited, whereas They are all invited except Larry means that Larry is not invited.