Definition
Disability is the want of legal capacity to exercise rights, perform acts with legal effect, or enjoy privileges and powers that would otherwise be available to a person. The term operates across multiple legal contexts and has undergone significant expansion of meaning from its classical sense to its modern regulatory usage.
Three distinct senses appear in legal materials:
1. CIVIL LEGAL INCAPACITY (classical meaning): The inability to exercise legal rights or perform legally effective acts, arising from status, condition, or operation of law. Historical examples include infancy (minority), coverture (the legal merger of a married woman's identity into her husband's), lunacy, alienage, and attainder. The incapacity may be total or partial, temporary or permanent.
2. PHYSICAL OR MENTAL IMPAIRMENT (modern regulatory meaning): A medically cognizable condition that substantially limits a person's ability to perform major life activities or, in the employment and benefits context, to engage in substantial gainful activity. This is the operative meaning in disability benefits programs (Social Security, VA) and anti-discrimination law (the Americans with Disabilities Act). Modern usage further recognizes that disability is shaped not only by impairment but by the interaction between impairment and societal barriers.
3. PERSONAL VS. ABSOLUTE DISABILITY (classical taxonomy): A personal disability attaches to a specific individual and arises from that person's status, prior acts, or natural or juridical incapacity. An absolute disability originates with a person but extends also to their descendants or successors — a concept relevant to inheritance and property transmission.
Common Language
Modern common usage (Wiktionary): A condition characterized by a significant limitation in a person's physical or intellectual powers or ability; also defined functionally as a limitation driven by the combination of individual impairment and societal inaccessibility.
Historical common usage (Webster's 1913): State of being disabled; deprivation or want of ability; absence of competent physical, intellectual, or moral power; also, want of legal qualification to do a thing.
The common-language and legal definitions share more surface overlap here than with many legal terms, but the divergence is significant in practice. Ordinary usage centers on physical or mental impairment. The classical legal meaning is entirely about legal status and incapacity — a married woman under coverture was legally disabled regardless of her physical or intellectual condition. Modern statutory law has shifted legal usage back toward the ordinary meaning, but the classical sense still governs historical materials. A researcher must know which era and which context they are working in to read either source accurately.
Common Confusion
CLASSICAL INCAPACITY VS. MODERN IMPAIRMENT
In pre-twentieth-century legal sources, "disability" almost always means legal incapacity arising from status — coverture, infancy, lunacy, attainder. It says nothing about a person's physical condition. In modern statutes and regulations, "disability" almost always means a medically defined impairment that limits function. These are not merely different shades of one concept; they are different institutions that happen to share a word. Reading a historical source's disability analysis through a modern impairment lens, or vice versa, will produce errors in both directions.
Recognized Forms
/SUBTYPES
PERSONAL DISABILITY: Incapacity that attaches to the individual and does not pass to heirs or successors. Arises from status (infancy, coverture), natural condition (lunacy), or legal consequence (alienage, attainder).
ABSOLUTE (HEREDITARY) DISABILITY: Originates with an individual but extends to descendants or successors. Relevant in property and inheritance contexts.
CIVIL DISABILITY: Specific legal rights suspended or forfeited by operation of law, typically as a consequence of criminal conviction — loss of voting rights, loss of capacity to serve on a jury, loss of right to hold office.
PHYSICAL/MEDICAL DISABILITY (REGULATORY): The modern sense. A medically determinable impairment that substantially limits one or more major life activities. The governing definition varies by statute — the ADA, the Social Security Act, and veterans' benefits law each apply their own definitions and thresholds.
TEMPORARY DISABILITY: Incapacity expected to resolve, often relevant in workers' compensation contexts.
PERMANENT DISABILITY: Incapacity not expected to substantially improve; relevant in both workers' compensation and veterans' benefits ratings.
Why It Matters in Research
The single greatest trap in researching disability across the Law Mind corpus is chronological and contextual mismatch. Historical legal dictionary entries — including all six sources indexed here — define disability exclusively in its classical civil incapacity sense. The concept of physical or medical disability as a legal category of its own, triggering affirmative regulatory obligations, is a twentieth-century development. It does not appear in Bouvier, Black's first or second edition, Anderson, Burrill, or Rapalje and Lawrence as anything more than a passing reference to natural incapacity as one ground for civil incapacity. Researchers working on modern disability law should use historical dictionaries only for definitional background on the incapacity tradition, not for substantive guidance on current doctrine.
Within the classical materials, coverage is uneven. Coverture as disability is extensively treated. Infancy is covered in its own entry across most sources. Lunacy and idiocy appear as disability grounds but are often cross-referenced rather than analyzed in depth under this heading. Attainder and alienage as sources of civil disability are mentioned but not developed. Researchers pursuing any of these topics should follow the cross-references to the substantive entries rather than relying on the disability heading alone.
For modern regulatory contexts, the three encyclopedia entries cross-referenced above are the primary navigational resources. The Social Security five-step sequential evaluation and the VA disability rating system are independent frameworks with distinct definitions of disability, distinct evidentiary standards, and distinct procedural requirements. A claimant who qualifies as disabled under one program does not automatically qualify under the other. Tax materials add a third framework — the Credit for Elderly and Disabled applies its own eligibility definition.
Researchers working in employment discrimination law (ADA, Rehabilitation Act) will find no support in the historical dictionaries. That body of law post-dates all shelf sources and requires engagement with statutory text, agency regulations, and case law directly.
One navigational note specific to historical property research: when historical sources describe an instrument or transaction as having been executed under a disability, the reference is to legal incapacity, not physical condition. The practical consequence — often an avoidance or ratification question — is resolved by the nature of the specific disability and the applicable limitations period, not by a medical inquiry.
Historical Dictionary Support
The six shelf sources are in substantial agreement on the classical definition. Black's first and second editions define disability as "the want of legal ability or capacity to exercise legal rights, either special or ordinary, or to do certain acts with proper legal effect, or to enjoy certain privileges or powers of free action." The second edition adds a case citation — Berkin v. Marsh, 18 Mont. 152 — connecting the definition to judicial authority. Both editions explicitly list married women, persons under age, insane persons, and felons convict as the paradigm cases of disability at the time of writing.
Anderson's Dictionary of Law provides the most analytically developed entry among the shelf sources, organizing the grounds of personal incapacity into three categories: want of sufficient understanding (lunacy and infancy), want of freedom of will (coverture and duress), and policy of the law (alienage, outlawry, and the like). This tripartite structure is useful for research purposes because it maps disability to its doctrinal source, which often determines the remedy.
Bouvier's entry is brief, directing researchers to substantive headings (Abatement, Devise, Deed, Infancy, Insanity, Limitation, Marriage, Parties) rather than developing the concept at this entry. Bouvier also includes a separate entry for Disabling Statutes — the Elizabethan acts restricting ecclesiastical and eleemosynary corporations from alienating land — which is a distinct and technical use of the disability concept in property law.
Burrill's entry is fragmentary in the indexed source, providing only a Latin-law root reference. Rapalje and Lawrence's indexed passage touches on disability in the context of statutory construction and performance obligations rather than defining the term directly.
No shelf source addresses physical or medical disability as an independent legal category. The absence is not an oversight; it reflects the state of the law at the time of publication.
Jurisdictional Note
The classical civil incapacity framework was broadly uniform across common law jurisdictions, though the pace at which specific disabilities were abolished varied. Coverture was eliminated earlier in some American states than others, and earlier in the United States generally than in England. Modern disability law — benefits programs, anti-discrimination frameworks, accommodation obligations — is entirely jurisdiction-specific and statute-driven. Federal programs (Social Security, VA, ADA) operate under federal definitions; state workers' compensation systems apply state-law definitions that differ materially from one another.