Difference between click and CTOR

What is the difference between click and CTOR. I am getting different percentages in my reports

Click to open rate (aka ctor or opens) measures when someone actively opens an email. This isn’t very valid a number though because differing email clients have different rules that define what an email open means and sometimes opens are reported that were not opens and vice versa.

Click through rates are specifically when someone clicks a link/button within your email. This number tends to be far more accurate because it usually requires a human actually doing something in order to register.