The term "SQR3" refers to a method of reading and studying. The method suggests readers become active in their learning in order to better comprehend and retain information. The letters stand for: Survey, Question, Read, Recite and Review.
A student should highlight important terms at the first R, which is the step of "reading." This is the step when we will first encounter the terms, and therefore, it will bring the most benefit to us to highlight them at this point.