IQ is a number meant to show how well you do on a certain kind of thinking test. The letters stand for intelligence quotient — an old, rather formal way of saying “a score for this kind of mental test.” 100 is set as the middle result; most people land near it. A higher number means a stronger score on that test, a lower number a weaker one. The tasks often involve patterns, memory, shapes, or numbers. Though actually, IQ is much narrower than “being smart.” It does not measure kindness, music, courage, or how well you handle people, and a score can shift a little with language, practice, and how you feel that day. In loose talk people say “high IQ” as a compliment without any test at all.