Words that start with U

You are upside-down when your head is lower than your feet. You can go upside-down hanging from play equipment like monkey bars, or if an adult holds you up by your feet. The world looks different when you are upside-down. When you turn anything else the wrong way up you say it is upside-down. Cats often lie upside-down with their legs in the air.

Uranus is the seventh planet from the sun. It takes 84 years to travel around the sun. Uranus is 2,870,972,200km from the Sun. Its radius is 25,559km.

A urinal is a toilet that is only used for urinating in. Urinals are usually found in men's bathrooms, and are designed for use by men. Men, of course, can urinate standing up. Women sit down.

Something is useless if there is no purpose for it. Something may become useless because it is broken and no longer does what it is supposed to do, or it might have never done anything to begin with.