One definition is: Type of trading attempted by a failed day trader before a final blow out. Which mirrors the definition of a day trading: Type of trading attempted by a failed swing trader before a final blow out.
Personally, I divide trading into two timeframes. Intraday trades,and swing trades. Swing trade in my own terminology is anything I hold overnight, doesn't matter if it is a two day trade or a six months trade. The length of the trade is determined by market conditions.