The National Association of Medical Examiners (NAME) makes the following distinctions between manners of death: 

Natural – “due solely or nearly totally to disease and/or the aging process.”  If natural death is hastened by injury (such as  a fall or drowning in the bathtub), then the manner of death is not natural. Some examples of Natural death are: heart disease, SIDS, chronic alcohol abuse, etc.  

Accident – “there is little or no evidence that the injury or poisoning occurred with intent to harm or cause death. In essence, the fatal outcome was unintentional”.  Some examples of Accidental death are: accidental overdose, falls, motor vehicle accidents, etc.   

Homicide – “occurs when death results from… an injury or poisoning or from “…a volitional act committed by another person to cause fear, harm, or death. Intent to cause death is a common  element but is not required for classification as homicide.” Homicide is when a person is killed by one or more persons.

This is different than murder. Murder is the unlawful taking of a human life by another, especially with premeditated malice.  For example, if a police officer kills someone in the line of duty, it is considered a homicide, but not necessarily a murder. All murders are homicides, but not all homicides are murders.  

Suicide – “results from an injury or poisoning as a result of an intentional, self-inflected act committed to do self-harm or cause death of one’s self.”  Some examples of Suicide are: drug overdose, gunshot hanging, etc. 

Undetermined – “used when the information pointing to one manner of death is no more compelling than one or more other competing manners of death when all available information is considered.”       

This is usually an interim classification that indicates a level of uncertainty about the circumstances surrounding the death. This classification is usually changed once the results of the autopsy are received.  Undetermined is intended for cases in which it is impossible to establish, with reasonable medical certainty, the circumstances of death after thorough investigation.

Pending Investigation - when determination of manner of death depends on further information,  usually prior to autopsy, external examination or test results.