What does it mean for a spacecraft to be “in orbit”?

A spacecraft is “in orbit” when it is circling around a planet (like Earth) continuously. It travels fast enough sideways so that even as gravity tries to pull it down, it keeps missing the planet and goes around instead. Being in orbit means the spacecraft is falling towards Earth but moving forward so quickly that it never actually hits the ground. This creates a path called an "orbit," which can last for months or even years if the spacecraft keeps its speed and altitude right.