In Ohio, a "dangerous dog" is defined as a dog that, without provocation, has caused injury to a person, or a dog that has been declared "dangerous" by a court of law. A dog may also be considered "dangerous" if it has killed another dog, or if it belongs to a breed that is commonly known as dangerous. Additionally, a dog may be considered "vicious" if it has caused serious injury or death to a person, or if it has been declared "vicious" by a court of law.