(an example of) serious crime that can be punished by one or more years in prison. (Cambridge Dictionary)
In countries where the legal system distinguishes between very serious crimes and less serious ones, a felony is a very serious crime such as armed robbery. (Collins Dictionary)
A grave crime formerly differing from a misdemeanor under English common law by involving forfeiture in addition to any other punishment. (Merriam – Webster)
A crime regarded in the US and many other judicial systems as more serious than a misdemeanour. (Oxford Dictionaries)
What Exactly is the So-called 3rd Degree Felony?