Definition
The killing of one's sister. As a descriptive term, sororicide refers both to the act itself and, less commonly, to the person who commits it. The term is borrowed from Latin and used primarily in taxonomic or academic discussion of homicide classifications rather than in operative legal language. No distinct crime of sororicide exists in modern statutory law; the act is prosecuted under standard homicide provisions — murder, manslaughter, or criminally negligent homicide — with the familial relationship potentially bearing on motive, sentencing, or, in some jurisdictions, eligibility for specific defenses or aggravating factors.
Common Language
Modern common usage (Wiktionary): The killing of one's sister.
Historical common usage (Webster's 1913): The murder of one's sister; also, one who murders or kills one's own sister.
The common and legal meanings are essentially identical in descriptive content. The critical gap is functional: in ordinary language the word names the act with apparent precision, while in law it carries no operative weight. Courts do not charge, convict, or sentence for "sororicide." The word may appear in scholarly writing, judicial opinions, or legal journalism as descriptive shorthand, but its presence signals nothing about how the underlying conduct is actually classified or punished.
Common Confusion
Sororicide is sometimes treated as a legal category parallel to parricide or infanticide. It is not. Parricide and infanticide have, in various jurisdictions and historical periods, carried distinct statutory definitions, separate charging instruments, or modified penalty schemes. Sororicide has never achieved that legal status. Researchers encountering the term in older legal writing should treat it as descriptive rather than doctrinal and look to the underlying homicide charge for legal substance.
Why It Matters in Research
The primary research trap here is treating a Latin-derived classificatory label as a legal term of art. Black's Law Dictionary itself flags the issue directly: "This is not a technical term of the law." That editorial note is the most important thing a researcher can know about this word.
When searching historical sources — particularly treatises, ecclesiastical records, or continental law materials translated into English — sororicide may appear as a genuine legal category. Canon law and some civil law traditions maintained more granular classifications of homicide by victim relationship than common law jurisdictions ever did. A researcher working with pre-modern English materials or comparative law sources should not assume that the term's use in a foreign or ecclesiastical context maps onto any common law category.
In modern sources, the word surfaces most often in forensic psychology literature, criminological studies of family violence, and academic legal scholarship examining honor killings or domestic homicide. In these contexts it functions as sociological shorthand, not as a charging category. Researchers building search strategies around homicide involving a sister should anchor searches in jurisdictional homicide statutes, aggravated assault provisions, and domestic violence enhancement language rather than the term sororicide itself.
The familial relationship between killer and victim is not legally irrelevant — it may affect charging decisions, sentencing enhancements, protective order history, or the applicability of domestic violence statutes — but those legal consequences flow from the relationship as a factual matter, not from the label sororicide.
Historical Dictionary Support
Black's Law Dictionary and Webster's 1913 are in full agreement on both meaning and scope. Both define sororicide as the killing (or murder) of one's sister and acknowledge the actor sense as secondary. Black's goes a step further than Webster's by explicitly stating that sororicide is not a technical term of the law — a clarification Webster's, as a general dictionary, had no occasion to make.
What neither source addresses is the term's genealogy in civil law and canon law traditions, where homicide classifications based on victim relationship were more formally developed. Researchers working in those traditions will find the absence of that context a genuine gap in the dictionary coverage.
No historical legal dictionary in the standard shelf corpus treats sororicide as having generated a body of case law, statutory treatment, or doctrinal elaboration. Its consistent treatment as a borrowed descriptive label rather than a legal term reflects the common law's general preference for classifying homicide by mental state and degree rather than by victim category.