Click-through rate
The share of recipients who clicked something in the email.
Click-through rate counts people who acted rather than people whose images loaded, which is why it survived the changes that undermined the open rate.
Read it together with what happened next. A high click rate with nothing following it usually means the email promised something the landing page did not deliver.
A related figure is click-to-open rate — clicks as a share of opens rather than of delivered messages. It inherits the open rate’s problems, so treat it with the same caution.