Conversion Rate:

The conversion rate is the number of conversions that happen on a website divided by the total number of site visitors.  To have a conversion rate you must first have a goal. Goals on a website can include a form submission, a purchase, a phone call, or even a certain length of duration on the site.

The process of optimizing your conversion rate is known as conversion rate optimization (CRO). This can involve A/B test to help identify which elements perform better.