Long term is the one you hold for a long time like for a year or so and for the short term you csn hold them for a month or less but if you want bigger profits you can go for the long term
If I need urgent cash, I go for short term trade so that I can get some profit very quickly. Otherwise I go for long term trade. Long term trade is usually more convenient compared with short term trade which is dangerous for the most of the coin traders.