A "plane" is a flat, two-dimensional surface that extends infinitely in all directions. In geometry, it is often represented by a shape like a rectangle or a square. You can think of a plane as a smooth tabletop where you can draw or place objects. It has no thickness and is defined by points, lines, and angles. In everyday life, the term "plane" can also refer to an airplane, which is a vehicle designed for air travel. Airplanes have wings and engines that allow them to fly high above the ground, connecting people and places around the world. Whether in math or aviation, planes play an important role in our understanding of space and travel.