Definition
Any morbid or disordered condition of the body that temporarily hinders or prevents its organs from performing their normal functions. The term has consistently been interpreted broadly enough to encompass mental as well as physical conditions, with both Black's and Bouvier's confirming that insanity falls within its scope.
In legal contexts, sickness appears most often in three settings: (1) contract and insurance law, where it defines the triggering condition for benefits under disability, health, or sick-pay provisions; (2) procedural law, where a party's sickness may excuse non-appearance, toll a limitations period, or delay service of process; and (3) tax law, where payments received on account of sickness receive distinct treatment under federal income exclusion rules.
Common Language
Modern common usage (Wiktionary): The quality or state of being sick or diseased; illness. Also, nausea or qualmishness.
Historical common usage (Webster's 1913): The quality or state of being sick or diseased; illness; disease or malady. Also nausea, as in sickness of stomach.
The common meaning and legal meaning are largely continuous, but a gap exists in two directions. First, ordinary usage tends to connote visible or felt physical suffering; the legal definition reaches conditions — including insanity — that may not present as conventionally physical ailments. Second, common usage is silent on degree and duration; legal instruments routinely impose durational thresholds (e.g., sickness lasting more than seven consecutive days) or severity requirements (total vs. partial disability) that have no parallel in everyday speech.
Recognized Forms
/SUBTYPES
Bouvier's draws a structurally useful distinction that survived into later insurance drafting:
General sickness: A condition affecting the body as a whole. Fever is the classical example. More likely to support total disability claims.
Local sickness: A condition affecting only a particular organ or part of the body. Blindness is the classical example. May support only partial disability claims depending on policy language, or may give rise to scheduled-benefit provisions.
This general/local distinction is not consistently maintained in modern statutory or regulatory language but remains relevant when interpreting older policy forms, benefit statutes, or pre-20th-century contracts.
Why It Matters in Research
Corpus researchers should be alert to several navigational issues:
Definitional instability across instruments. "Sickness" rarely appears in isolation in operative legal documents. It is almost always paired with, distinguished from, or subordinated to "disease," "illness," "injury," or "disability." The legal weight of the term depends entirely on the surrounding instrument. An insurance policy that covers "sickness" but not "injury" has spawned substantial litigation over which category controls; a tax exclusion keyed to "sickness" has a statutory meaning shaped by the Internal Revenue Code rather than common law. Do not assume definitions transfer across contexts.
The insanity inclusion is non-obvious and historically significant. Both historical dictionaries cite the same English authority (L.R. 8 Q.B. 295) for the proposition that insanity constitutes sickness. This was not self-evident in periods when mental illness was categorized separately from bodily disease. Researchers working with 19th- or early 20th-century instruments should not assume that "sickness" provisions in those documents were understood to cover mental conditions unless the instrument or controlling authority made that explicit. The modern statutory trend has generally moved toward explicit mental health parity language rather than relying on definitional extension of "sickness."
Tax law gives the term a distinct statutory life. The federal income tax exclusion for amounts received on account of personal injury or sickness creates a specific legal category that is not coextensive with the common law or insurance definitions. Researchers analyzing compensation, damages, or benefit payments for tax purposes must consult the Tax Encyclopedia entry and the applicable statutory and regulatory framework rather than importing definitions from tort or contract sources.
Procedural uses require attention to local rules. Sickness as a ground for continuance, excuse from appearance, or tolling of limitations is highly jurisdiction-specific and often governed by court rule rather than statute. Historical sources treat this application but their procedural context may not map onto modern practice.
Historical Dictionary Support
Black's (both editions) and Bouvier's are in near-complete agreement, all three tracing their authority to the same English case citation. The definitions are functional rather than clinical: sickness is defined by what it does (prevents normal organ function) rather than by pathology. This functional framing is jurisprudentially significant — it oriented courts toward the effect on the person rather than toward medical diagnosis, which gave the term flexibility across changing medical understanding.
Bouvier adds the general/local distinction that Black's omits, making Bouvier the more granular source for researching benefit disputes that turned on whether a condition was systemic or localized. Bouvier also begins a discussion of sickness as a procedural ground for excusing a party from process, though the entry is truncated in surviving sources.
Neither historical dictionary addresses the tax dimension — unsurprisingly, given that the federal income tax as a permanent institution postdates both editions in their primary forms. The gap between the historical dictionaries and modern research needs is most acute in the tax context.
Jurisdictional Note
State workers' compensation and disability benefit statutes vary considerably in how they define sickness relative to injury and occupational disease, and whether mental conditions qualify under sickness provisions. Researchers should not assume that the broad historical definition — which included insanity — reflects the operative definition in any particular modern statutory scheme. Federal tax treatment of sickness benefits follows Internal Revenue Code provisions and Treasury regulations that operate independently of state law definitions.
Encyclopedia Cross-Reference
Exclusions — Compensation for Injuries and Sickness, The Law Mind Tax Encyclopedia