Yes, IQ stands for “intelligence quotient” in the context that someone can be asked to take a test with X questions and T time to complete, and a calculation involving division will yield a useful number to approximate their intelligence in some sense. It’s one attempt to measure intelligence as a single test score.
Intelligence itself is a far broader concept. Studies of intelligence by people trying to understand more of the fullness and subtlety of the subject (as opposed to trying to reduce it to a convenient single number for education/industry purposes) recognize that there are many different types of mental capacities. (e.g. in 1983, Howard Gardner invented a framework that posited 9 types of intelligence .) Others have noticed that many (or, it seems to me and others) all people have some sort of personal genius, and it may be more useful to search for that rather than to reduce to certain categories and evaluate those.
There is a much more serious problem than lack of accuracy with rating intelligence as a numeric score, or even of evaluating 9 types of intelligence: it creates an inaccurate comparison system that suggests that some people are deficient. It also encourages people to work on improving scores or ways of thinking that may not match their actual genius, which can actively interfere with their ability to find their actual genius, and also to mess with their self-esteem and feelings of worth and belonging.