What is Day Trading / Intraday Trading?

As the name suggests each stock price has an opening price for any given day. But as the day progresses it takes on either a positive trend or a negative trend depending on the market conditions. The maximum price point that the stock has reached on a given trading day is the day high for that particular stock. Opposite to that the minimum price point reached by that stock on that day is the day low price. Before the market closes the day high and day low prices are subject to change.