A satellite is an object that orbits something else. An object in orbit is in continual freefall, moving forward so fast it never hits the ground. The closest point of an orbit to Earth is termed perigee, and the furthest point is apogee. An orbit is the path around another object in space.
Space travel became a seriously considered engineering endeavour through the works of Konstantin Tsiolkovsky. To access space a dedicated vehicle is required, a launch vehicle. Multistage rockets are two or more rockets, or stages working in sequence. Once a stage has completed its burn it is jettisoned.
As altitude increases the air gets thinner, that is, atmospheric density decreases. The nominal boundary to space as the von Kármán ellipsoid, a curve, above the surface of the Earth at 100km altitude. A spacecraft is a vehicle or vessel designed to operate beyond the von Kármán ellipsoid. The only thing we all agree on is that space is up.
Nibbles in Space is a series of short podcasts, making space more accessible. A nibble is half a byte. A nibble is 4 bits of information, whether you listen to it as a podcast or if want a little more of a Nibble you can read it at SpaceProf.xyz/Nibbles.