Definition
The termination of a pregnancy before the fetus is capable of sustaining independent life outside the womb. The term encompasses two fundamentally different categories that modern law treats separately:
1. Spontaneous abortion (miscarriage): The natural, unintended expulsion of a fetus or embryo, carrying no legal consequence for the pregnant person.
2. Induced abortion: The deliberate termination of a pregnancy through medical or surgical means. The legal status of induced abortion — whether it is a protected right, a regulated procedure, a criminal act, or some combination depending on gestational stage — is the central question of abortion law and has undergone radical transformation across American legal history.
For most of the twentieth century, federal constitutional doctrine governed abortion law nationwide, establishing a framework of protected reproductive choice subject to state regulation. Since Dobbs v. Jackson Women's Health Organization (2022), constitutional protection under federal law no longer exists, and abortion's legal status is determined almost entirely by individual state law.
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Common Language
Modern common usage (Wiktionary): The expulsion from the womb of a foetus or embryo before it is fully developed, with loss of the foetus; encompasses both spontaneous miscarriage and induced termination; also used colloquially for the abandonment or failure of any project or undertaking.
Historical common usage (Webster's 1913): The act of giving premature birth; expulsion of the human fetus prematurely or before it is capable of sustaining life; miscarriage; also, arrest of development of any organ, or any fruit or produce that does not come to maturity.
The gap between common and legal meaning is significant in two directions. First, ordinary language uses "abortion" to include both spontaneous miscarriage and induced termination interchangeably, while law has increasingly separated these into distinct categories with entirely different legal consequences. Second, the common colloquial extension of the word — an abandoned project, a failed endeavor — has no legal valence whatsoever and should alert researchers that non-legal historical sources using the term may not be discussing reproductive medicine at all.
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Common Confusion
Abortion / Miscarriage: In common speech these are often used interchangeably for spontaneous pregnancy loss. In law, the distinction is consequential: criminal abortion statutes, reporting requirements, and liability frameworks attach only to induced procedures. Historical statutes frequently used "miscarriage" as a synonym for induced abortion (the procuring of miscarriage), which is the reverse of modern common usage. Researchers reading nineteenth- and early twentieth-century statutes must determine from context whether "miscarriage" refers to a spontaneous event or to an induced act.
Abortion / Feticide: Some modern state statutes separately criminalize the killing of a fetus through violence against a pregnant person (feticide or fetal homicide). These are distinct from abortion statutes and operate under different elements, defenses, and policy rationales.
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Why It Matters in Research
The post-Dobbs landscape is the defining research challenge. Before 2022, a researcher could assume a baseline federal constitutional framework — rooted in Roe v. Wade (1973) and modified by Planned Parenthood v. Casey (1992) — and then examine state law as a set of variations on that framework. That architecture no longer exists. State law is now primary and largely dispositive. The Law Mind corpus reflects both eras, and researchers must anchor every source temporally: a 2015 analysis of a state abortion statute may describe a regulatory scheme that was either invalidated or dramatically transformed after Dobbs.
Quickening as a historical threshold: The historical sources in the Law Mind corpus are organized around the concept of quickening — the point at which fetal movement is first felt by the pregnant person, approximately sixteen to twenty weeks. Before quickening, the common law recognized no criminal offense; after quickening, induced abortion could be prosecuted. This distinction is absent from modern law (which replaced it with viability and, after Dobbs, with gestational bans that in some states begin at fertilization), but it is the operative framework in all pre-twentieth-century legal sources and many nineteenth-century statutes. Researchers using historical materials must hold this framework carefully to avoid misreading what the sources actually prohibited.
Terminology drift in statutes: The word "miscarriage" in statutes predating the mid-twentieth century almost always means induced abortion — the procuring of a miscarriage. Modern statutes use "abortion" for induced termination and treat spontaneous pregnancy loss as outside the regulatory framework entirely. Cross-era statutory research requires constant attention to this drift.
Criminal versus civil frameworks: Contemporary abortion law operates across multiple legal registers simultaneously — criminal prohibitions on providers, civil liability schemes (including private rights of action by third parties), licensing and facility regulations, insurance coverage mandates or prohibitions, and, in some states, constitutional protections. Historical dictionary sources address only the criminal law dimension, which was the sole legal register at the time of their composition. Researchers must supplement with administrative, constitutional, and tort law sources to understand the full modern picture.
Interstate dimensions: Post-Dobbs, questions of whether one state's laws can reach conduct occurring in another state — travel for abortion services, provision of medication abortion across state lines — have generated new legal disputes with no settled doctrine. Historical conflict-of-laws principles are being applied to a novel factual context. Corpus sources on conflicts of law and extraterritoriality are directly relevant.
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Historical Dictionary Support
The historical dictionaries are in substantial agreement on the basic definition: abortion is the premature expulsion of the fetus before it is capable of sustaining independent life. All five sources frame the legal discussion in criminal law terms, reflecting the historical reality that abortion was primarily a criminal law subject.
Burrill's is the most technically precise of the group, explicitly limiting the criminal offense to abortion "after the period of quickening" — stating the common-law rule plainly. This is the formulation that accurately captures English common law as it was received in American jurisdictions. Black's (both editions) and Anderson's follow a similar line without always being as explicit about the quickening threshold. Bouvier's takes the most medical approach, cataloguing natural causes of miscarriage and their clinical origins, which is useful context for understanding how nineteenth-century law distinguished spontaneous from induced cases.
All five sources reflect a world in which abortion after quickening was a crime, period — there is no discussion of constitutional protection, patient rights, gestational frameworks, or regulatory licensing because none of those concepts applied at the time of composition. This is their primary limitation for modern research: they describe the common-law baseline accurately but offer no guidance on the century of statutory revision, constitutional litigation, and post-Dobbs reordering that followed.
What the historical sources miss entirely: the concept of viability as a legal threshold (a twentieth-century medical and constitutional development), federal constitutional protection and its removal, the distinction between provider liability and patient liability (modern statutes almost universally exempt pregnant persons from criminal prosecution, a policy choice with no historical counterpart), and the emergence of civil enforcement mechanisms.
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Jurisdictional Note
Abortion law is among the most jurisdictionally variable areas of American law. Following Dobbs, states range from complete prohibition from fertilization or a specified early gestational stage, to affirmative constitutional protection of abortion rights under state constitutions. No general statement about the law's content is accurate across all jurisdictions. Researchers must identify the specific state and the specific time period before relying on any source.
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