The term "20/20" refers to a standard measurement of visual acuity, which indicates how well a person can see at a distance. If someone has 20/20 vision, it means they can see clearly at 20 feet what should normally be seen at that distance. This measurement helps eye care professionals assess and compare vision quality. In addition to vision, "20/20" is often used metaphorically to describe clarity of understanding or hindsight. For example, people might say, "In hindsight, my decision was 20/20," meaning they can see the situation clearly now, even if it was confusing at the time.