Stereophonic means using two separate channels of sound to create a more realistic, three-dimensional listening experience. When you listen to stereophonic sound (often shortened to stereo), different sounds come from different speakers, just like how your two ears hear sounds coming from different directions in real life.

Before stereo, recordings were monophonic (or mono), meaning all the sounds mixed together came from a single speaker. Imagine watching a movie where everything appears flat on the screen versus seeing it in 3D. That's similar to the difference between mono and stereo sound.

When you wear headphones and hear the drums in your left ear and the guitar in your right ear, that's stereophonic sound at work. Your brain combines these two channels to create the sensation that musicians are positioned in different locations around you. A good stereo recording can make you feel like you're sitting in the middle of an orchestra, with violins to your left and cellos to your right.

Most music, movies, and video games today use stereophonic sound, or more advanced systems built on the same basic principle.