You are interested in understanding how clicks lead to a sale on your site. What do you call a click that leads to a sale on your site?
Conversion
Impression
Cost-per-click
Clickthrough rate
Explanation:
When a click leads to sale or to a desired action, it is called conversion. It can be a completely filled form, app download, sign-up for newsletter or clicking to a button. Conversion can be tracked using conversion tracking mechanism.