Beside or Besides

Besides is not the plural of beside. They are not interchangeable.
Beside is a preposition of place that means next to.
Besides means in addition to or also.

  • The man is standing beside his new car.
    (next to his new car)
  • There are many other places we can visit besides Turkey.
    (in addition to Turkey)
  • Besides, I need to tell you I saw yesterday.
    (Also, I need)