Your home recording studio hardware, namely mixers (if you have one) and/or audio interface boxes will have places where you can poke cable plugs into them. Not surprisingly these are called inputs. But lest you think that's the end of the story, just a simple hole designed for one and only one kind of plug/cable carrying one and only one kind of audio, you'd better think again. There are frequently choices to be made by pressing a button down or leaving it in the "unpressed" position, depending on what kind of "level" you are dealing with. These types are usually line, instrument or microphone (mic) levels.
Here is an article explaining what the difference is: