Definition
A bright-line, common law rule that a person cannot be convicted of homicide for a death that occurs more than a year and a day after his or her act(s) that allegedly caused it. The rule arose from the difficulty of determining cause of death after an extended period of time. Like most common law principles, state legislatures or courts may modify or abolish this rule.
Illustrative caselaw
See, e.g. Rogers v. Tennessee, 532 U.S. 451 (2001).