What is Relative Strength? ?

What is relative strength? http://www.financial-spread-betting.com/course/introduction-relative-strength-analysis.html PLEASE LIKE AND SHARE THIS VIDEO SO WE CAN DO MORE. The official definition is that you get XYZ stock and you divide it by another stock's value (say ABC stock) and you get the ratio. But what use is this to us as traders? How can we use it in our own trading? We have a stock and we want to see if that stock is relatively strong compared to the market. Says if the wider market goes down but ABC's stock price holds ground this tells us that buyers of ABC stock have kept holding their shares. it is the same with relative weakness