A more thorough explanation:

Cannibalism is the act of consuming another human's body matter, whether with or without their consent. In the United States, there are no specific laws against cannibalism, but most states have laws that indirectly make it impossible to legally obtain and consume human body matter. For example, murder is a likely criminal charge regardless of any consent. Even if someone consents to being eaten and ends their own life, the cannibal may still be liable for criminal or civil actions based on laws governing the abuse or desecration of a corpse, which vary by jurisdiction.

One example of cannibalism is the case of Regina v. Dudley and Stephens. In this English criminal case from the 19th century, two men and two other shipmates were marooned on a raft after their vessel was destroyed in a storm. They had no fresh water and little food. In desperation, one of the men drank sea water to slake his thirst, but it only made him sick with dehydration and eventually he lost consciousness. Dudley then killed him, and the three survivors drank his blood and ate his body for the next week before being rescued. Despite the dire circumstances and evidence that the victim was near death anyway by the time Dudley killed him, the defendants were found guilty and sentenced to death. Their sentences were later commuted to six months in prison.

Another example is the case of Armin Meiwes, a German man who found someone through a cannibalism fetish website to consent to being killed and eaten. After meeting, Meiwes killed the victim and butchered his body, freezing the meat for future consumption. Meiwes was apprehended and arrested several months later. Although cannibalism was not illegal in Germany, Meiwes was initially convicted of manslaughter. He later received a retrial at the prosecutors' request and was convicted of murder.

These examples illustrate the definition of cannibalism by showing the consumption of human body matter, whether with or without consent, and the legal consequences that can result from such actions.