A unicorn is a mythical creature that resembles a white horse with a horn in the center of its forehead. Unicorns were said to have many powers, such as being able to cure disease and purify water. It is said that unicorns could only be captured by a virgin.
A unicycle is a bicycle with only one wheel. The "uni" at the start of the word means one, just like the "bi" on bicycle means two, and the "tri" on tricycle means three. Because unicycles only have one wheel they are hard to ride and hard to steer, and they are not seen very often outside of circuses.
Something is uniform if it is the same everywhere. A wall that is all one color might be described as being a uniform shade of green. A uniform is also the name given to the clothing all people in an organisation have to wear so they all look similar. People in the military wear uniforms, and many schools require that children wear uniforms. Uniforms for men and women are often quite different, even in the same organisation.
Something is unique if there is nothing else like it. When something is unique, there is only one thing of its kind.
The universe describes all known matter and space. All of the planets and galaxies in existence are part of the universe. Another word for universe is cosmos.
A university is a place where people go, usually after finishing school, to learn more about something so they can get a job, or simply because they love to learn. Universities give you a degree or some other certification when you have finished learning. In some countries, a place where you go for other kinds of tertiary education is known by other names, like a college or a technical school.
Someone is unkempt if they haven't paid attention to their personal hygiene and grooming, and look very scruffy. Something like a garden is unkempt if it has been unmaintained and left to get overgrown.
You unload something when you take the load or cargo out from inside it. The truck in the picture is unloading a pile of dirt.
A book or any other piece of writing is unread if you have not read it. Once you have read a book, and then give it to someone else who hasn't read it, it becomes unread again to the new person.