What is a day trade?

FINRA rules define a day trade as buying then selling or selling short then buying the same security on the same day. Stocks and options are both subject to day trade counts.  

At TradeUP Securities, day trades are calculated based on the number of opening orders on that day. For example, if a client makes the following orders:
(OPEN) Buy 15 shares of XYZ
(OPEN) Buy 15 shares of XYZ
(CLOSE) Sell 10 shares of XYZ
(CLOSE) Sell 10 shares of XYZ
(CLOSE) Sell 10 shares of XYZ

The client would be considered to have made 2 day trades because there are only 2 opening orders.