Trading exchange of shares on the market for certain time frame. For day trading, it would be an intra-day time frame. Intra-day means trade during a single day only, not over many days. Day trading can last for a few moments or up until the closing of the market. The key thing to keep in mind is that the equity is bought and sold on the same day.
Day traders are reacting on intra-day moves in the markets and stocks. They are looking for intra-day support and resistance area and inflection areas. Inflection areas are certain levels to buy that will give follow through either to the upside or downside.