Something that is "tilted" isn't straight up and down. It leans to the side a little bit. Things that can be tilted include:

• someone's head
• a picture frame
• an airplane that's flying in the air

Notice that "tilted" is different from "crooked" or "curved". These words both also mean "not straight", but in different ways:

• "Crooked" means that something bends in different directions at sharp angles, like a tree branch.
• "Curved" usually means that something bends smoothly in different directions, kind of like the letter "S".
• When something is "tilted", it can still be straight, but it's just not pointed directly upwards.