Click-through rate is clicks divided by impressions: the share of times your result was shown that someone clicked it. In Google it depends heavily on position.
Click-through rate, or CTR, is clicks divided by impressions: the share of times your result was shown that someone clicked it. 30 clicks from 1,000 impressions is a 3% CTR.
In Google, CTR depends mostly on position. In Backlinko's study of 4 million results, the first organic result averaged 27.6%, and page two collected 0.63% of clicks in total. An AI Overview above the results lowers it further: a Pew Research Center study found people clicked a normal result on 8% of visits with an AI summary against 15% without.
A low CTR at a high position usually means the title or description does not match the search. See why you get impressions but no clicks.