A rudder is a device that is used to steer a boat, hovercraft or aircraft. It works by changing the direction the air or water rushes past the vessel. Rudders are typically seen on the back of ships, behind the propeller. Rudders on airplanes are mostly to add stability rather than for steering.
A rug is a piece of small carpet that doesn't cover the entire room. Some people call rugs carpets too. They often have a fringe around the edge, or a bright pattern on them. Rugs are usually bought to look good.
A rule is something that tells you how you are expected to behave. Rules can be written down, or just something you are expected to know. Some rules are enforced by punishments. A set of rules that affects everyone in a large area is called the law.
A ruler is a thin, hard, straight piece of plastic or wood with numbers written on the edges at even spacings. Rulers are used both for drawing straight lines, and for measuring how long things are.
An animal's rump is its fleshy hindquarters, bottom or buttocks. A cut of meat taken from an animal's rump may have the same name, for example rump steak.
