Output is defined as cryptocurrency going out of your digital wallet.

Cryptocurrency coming into your digital wallet is known as an “input”.

Let’s say you want to spend 10 bitcoin, if you have 3 inputs (3, 9, and 15) then the first two are combined (3+9=12) and both are sent out as outputs.After transaction fees are spent, the remaining balance (about 2 bitcoin) is sent back to you as an input.

Your output is always another person’s input. And reversely, your input is always another’s output.