Definition
Polygamy is the practice of having more than one spouse at the same time. As a criminal offense, it is the act of marrying, or knowingly living in a marriage-like relationship with, multiple spouses simultaneously — whether multiple wives (polygyny) or multiple husbands (polyandry) — while a prior marriage remains valid and undissolved.
In American legal history, polygamy carried a specific statutory and constitutional charge beyond the general criminal prohibition: it was treated as a status offense as well as a conduct offense. Federal legislation, particularly targeting the practice in Utah Territory, criminalized not only the act of plural marriage but the continued maintenance of that marital status — meaning a man who continued to cohabit with multiple wives could be prosecuted even if the underlying marriage ceremonies predated the statute.
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Common Language
Modern common usage (Wiktionary): The condition of having more than one spouse or marriage partner at one time; sometimes used as a synonym for polygyny (one husband, multiple wives); also used loosely to mean having more than one sexual mate.
Historical common usage (Webster's 1913): "The having of a plurality of wives or husbands at the same time; usually, the marriage of a man to more than one woman, or the practice of having several wives, at the same time."
Ordinary usage of polygamy is broader and more morally descriptive than the legal term. Colloquially, the word is often applied to informal plural relationships, religious communities with non-legally-recognized plural unions, and even animal mating patterns. In law, polygamy has a precise criminal definition requiring (in most formulations) an actual marriage ceremony or legally cognizable marital act — not merely cohabitation or religious solemnization without civil recognition. The distinction matters for charging decisions and constitutional challenges.
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Common Confusion
Polygamy and bigamy are frequently conflated, including in the historical sources themselves. The historical distinction is: bigamy was the canonical term for a layman's second marriage while the first spouse lived; polygamy described the broader practice of maintaining multiple spouses simultaneously. In modern American statutory law, the terms have largely merged. Most states use bigamy as the operative offense, defining it broadly enough to encompass conduct that the old sources would have called polygamy. Burrill's Law Dictionary acknowledges this directly, noting that "in modern law the term has been dropped, and bigamy, a term of the canon law, expressive of a different and more general idea, has been substituted." Bouvier reinforces this: "bigamy is now commonly used even where polygamy would be strictly correct." Researchers should not assume that a historical source's use of one term excludes the conduct described by the other.
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Why It Matters in Research
Terminological instability is the central research hazard. Polygamy and bigamy are used interchangeably across centuries of sources, and a researcher who searches only one term in historical corpora will miss significant material. This is not merely sloppy usage — it reflects genuine doctrinal uncertainty about whether polygamy was a distinct offense or simply an aggravated form of bigamy.
The federal dimension is critical and underrepresented in the general dictionary entries. Nineteenth-century federal anti-polygamy legislation (the Morrill Anti-Bigamy Act of 1862, the Edmunds Act of 1882, and the Edmunds-Tucker Act of 1887) created a body of law that treated polygamy as a threat to republican institutions, not merely a marital irregularity. Courts interpreting these statutes addressed voter disqualification, property rights of polygamous families, and territorial governance in ways that extended far beyond simple criminal prosecution. Researchers working in constitutional history, religious liberty, or federal-territorial relations will find polygamy deeply embedded in those bodies of law.
The religious liberty intersection is significant for modern research. Post-Reynolds v. United States (1879), the doctrinal framework treated polygamy as conduct unprotected by the Free Exercise Clause even when religiously motivated. That holding has been repeatedly revisited in scholarship, though its core holding has not been overruled. Any Law Mind corpus research touching First Amendment religion doctrine should treat polygamy cases as a foundational strand.
Voter and civic disqualification statutes are a related research trap. As the Black's entry fragments indicate, maintaining polygamous status — not merely committing the act — could disqualify a person from voter registration independent of any criminal conviction. This civil-disability dimension of polygamy law is easy to miss if research focuses only on criminal codes.
Modern developments in several jurisdictions have decriminalized simple cohabitation in plural relationships while retaining criminal penalties for civil marriage fraud (obtaining a second marriage license). This distinction between religious or informal plural unions and legally bigamous marriages has created a new layer of doctrinal complexity that the historical dictionaries do not anticipate.
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Historical Dictionary Support
The historical sources agree on the core definition — multiple simultaneous spouses — but diverge on the relationship between polygamy and bigamy. Bouvier and Burrill are the most analytically careful, both acknowledging that the terms have traded places in common legal usage. Bouvier notes the cross-contamination explicitly: "polygamy is used where bigamy would be strictly correct," citing Massachusetts statutory usage as an example of the confusion embedded in official law.
Rapalje & Lawrence gives the shortest entry — "plurality of wives or husbands" with a cross-reference to bigamy — which is characteristic of that dictionary's tendency to subordinate closely related terms. Anderson's Dictionary of Law does not appear to have provided a substantive polygamy entry in the retrieved fragments, reflecting perhaps the term's absorption into bigamy doctrine by the time of that dictionary's compilation.
Black's (both editions) adds the dimension of status maintenance: the offense was not limited to the moment of the marriage ceremony but extended to knowingly maintaining the polygamous relationship. This is significant because it affected the statute of limitations analysis and the elements required for prosecution. The First Edition fragment explicitly connects polygamy to voter disqualification under territorial law, confirming that the term had legal significance beyond the criminal docket.
What the historical dictionaries collectively miss is the constitutional architecture that developed around polygamy in the federal territorial context. They treat it as a criminal law entry when it had become, by the 1880s, a major site of constitutional adjudication involving federalism, religious liberty, and the civil rights of territorial residents.
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Jurisdictional Note
Polygamy remains a criminal offense in all U.S. states, though the operative statute is almost always captioned as bigamy. A minority of states have recently narrowed enforcement to cases involving a fraudulently obtained second marriage license, effectively decriminalizing religious or informal plural cohabitation. Canadian law similarly criminalizes polygamy under Section 293 of the Criminal Code, and the constitutionality of that provision under the Canadian Charter was upheld in Reference re: Section 293 of the Criminal Code of Canada (2011). International variation is substantial: polygyny is legally recognized in numerous jurisdictions across Africa, the Middle East, and South Asia.
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Encyclopedia Cross-Reference
See Law Mind Encyclopedia — Marriage, Plural Marriage and the Law; Bigamy and Related Offenses; Free Exercise of Religion (Historical Doctrine)
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