Real Dictionary

felony
countable noun: 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.

felony in American English
a major crime, as murder, arson, or rape, for which statute usually provides a greater punishment than for a misdemeanor: the usual minimum penalty is imprisonment for one year
noun: an offense, as murder or burglary, of graver character than those called misdemeanors, esp. those commonly punished in the U.S. by imprisonment for more than a year

felony in British English
noun: (formerly) a serious crime, such as murder or arson. All distinctions between felony and misdemeanour were abolished in England and Wales in 1967