What is a 'conversion'

I am a super ‘newbie’ to affiliate marketing, so everything is new for me.
What does it mean when I have a conversion? Is it a sale?

Yes, if you’re tracking sales a conversion is a completed sale. In general however a conversion can refer to any desired action that you want the user to take.

Thanks. I didn’t realize that one needs to select what definition of ‘conversion’ one wants to track, or that there were different options. Learning goes on.