Some common expressions with “side”

side by side = next to each other

They sat side by side on the sofa, holding hands.

on the side = in addition to your main job

She works at a school, but she also gives private lessons on the side. look on the bright side = see things in a positive way

I’m sorry you’ve lost your wallet, but let’s look on the bright side. At least we still have enough money to get home.

upside down = the top is where the bottom would normally be: Careful! You’re holding the box upside down. Everything will fall out.

inside out = the inside is facing outwards. This expression is often used when talking about clothes:

He wore his pullover inside out, but nobody noticed.