What is a sound card?

I am attempting to use software that uses a sound card for audio. I need to know what it is exactly before I get any further into it.

A sound card is basically what allows your computer to make sound. Basically when you play music that's what allows you to hear it from the computer.

In older computers the sound card plugs into a slot in the computer and you plugged your speakers and mike into it in the back. On newer computers the sound system is built into the mother board. If your speakers don't plug into a card in a slot, yours works that way. If you look closely at the jacks where you plug in the sound, you will see symbols that represent a microphone and a speaker. Usually the speaker is green. They are the input and output to the sound card.