Misdemeanors are crimes that do not rise to the severity of a felony. They are lesser crimes for which the maximum sentence is 2 years or less in jail. The distinction between misdemeanors and felonies lies within the seriousness of the crime. Aggravated assault (beating someone with a baseball bat, for example) is a felony, while simple assault (slapping someone in the face) is a misdemeanor.
But some crimes that are usually treated as misdemeanors in the courts, can rise to the level of a felony under certain circumstances. For example, in some states, possession of less than an ounce of marijuana is a misdemeanor, but possession of more than an ounce is considered possession with intent to distribute, a felony.
Likewise, an arrest for driving under the influence is usually a misdemeanor, but if anyone was hurt or killed or if it is not the driver’s first DUI offense, the charge can become a felony.