Crimes in New York are defined by what the punishment can be. So that crimes that are punishable by less than 1 year in jail are misdemeanors, and those crimes that are punishable by more than 1 year in jail are felonies.
There are varying degrees of both misdemeanors and felonies.
For misdemeanors there are both A misdemeanors and B misdemeanors. And with felonies they are categorized as E through A, with A felonies being the most serious: kidnapping, murder, and other crimes that hold many years of incarceration if you’re convicted.