The buying and selling of financial instruments (derivatives, forex, commodities, etc) in an attempt to make a profit the same day. While all trading is done with the aim of making a profit, what sets day traders apart is they rarely hold a position overnight (or while the market is closed). Historically, day trading was only available to professional traders and financial institutions, but with the advent of the internet and more widespread use of trading technology, more and more individuals are able to make use of day trading.
We don't know everything about the markets. We're just devoted to learners. Taken from those smarter than ourselves, here's how we define Day Trading.