Definition
In law, age refers to the period of a person's life that determines their legal capacity, rights, obligations, and exposure to liability. Unlike the ordinary sense of age as mere duration of existence, the legal concept is functional: age is legally significant only insofar as reaching or failing to reach a specified threshold enables or disables a person from performing a legally recognized act.
Age operates differently across legal contexts:
1. Age of majority. The threshold — historically fixed at 21 years at common law, now typically 18 by statute in most U.S. jurisdictions — at which a person acquires full legal capacity to contract, sue, hold property, vote, and manage their own affairs without a guardian or next friend.
2. Age of consent. The minimum age at which a person is legally capable of consenting to sexual activity, marriage, or medical treatment. Varies by jurisdiction and by subject matter.
3. Age of criminal responsibility. The minimum age below which a person cannot be held criminally liable, on the premise that a child lacks the capacity to form the requisite mental state. At common law this was presumptively set at 7 years, with a rebuttable presumption of incapacity continuing to age 14.
4. Age as a factor in civil status. Age determines eligibility for specific legal statuses and entitlements — including retirement benefits, the right to make a will (testamentary capacity), the capacity to enter certain regulated industries, and mandatory retirement thresholds in some contexts.
5. Age as evidence. In evidentiary and procedural contexts, a person's age may bear on competency to testify, on damages calculations, or on the application of specific statutory protections.
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Common Language
Modern common usage (Wiktionary): The amount of time a being has been alive, or a thing has been in existence, measured from birth or origin to the present or another reference point. Also, the state of being old; any particular stage of life.
Historical common usage (Webster's 1913): The whole duration of a being; that part of its duration between its beginning and any given time; the latter part of life; an advanced period or state of being old.
The gap between common and legal meaning is one of function versus duration. In ordinary usage, age is descriptive — a measure of elapsed time. In law, age is operative: it triggers or extinguishes legal capacity, rights, and liability. A researcher reading historical legal sources should not assume that references to "age" denote a biological fact being recorded; they denote a legal threshold being applied or disputed.
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Common Confusion
Age and infancy are frequently conflated in historical sources. "Infancy" in law is a term of art meaning the status of a person below the age of majority — it has nothing to do with being an infant in the common sense. A 19-year-old was an "infant" at common law until reaching 21. Researchers reading equity pleadings, contract disputes, or tort records from before the twentieth century should understand that "infant" and "person of full age" are the operative legal categories, not biological descriptions.
Separately, the age of majority and the age of consent are distinct thresholds that may not coincide. Reaching majority does not automatically establish consent capacity for all purposes, and in some historical jurisdictions the age of consent to marriage was substantially lower than the age of majority.
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Recognized Forms
/SUBTYPES
Age of majority — Full legal capacity; historically 21, now generally 18 by statute.
Age of consent — Capacity to consent to marriage, sexual activity, or specific contracts. May differ by subject matter within the same jurisdiction.
Age of criminal responsibility — Below this threshold, no criminal liability attaches. Common law fixed a presumptive floor at 7, with qualified incapacity to 14.
Age of testamentary capacity — Minimum age to execute a valid will; typically 18, though some jurisdictions permit earlier execution by emancipated minors or members of the armed forces.
Presumed age — Where age cannot be determined from records, courts have historically applied presumptions; this arises most frequently in historical property, succession, and immigration cases.
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Why It Matters in Research
Age is one of the most jurisdictionally and temporally unstable legal thresholds in the corpus. Researchers must be careful on several fronts:
The age of majority was 21 at common law and remained so in most American jurisdictions until the early 1970s, when widespread statutory reform — driven in part by the Twenty-Sixth Amendment's extension of the voting franchise to 18-year-olds — reduced it to 18 across most states. A contract case from 1950 involving a 20-year-old will likely treat that person as a legal infant; the same fact pattern today would not. Reading contract capacity decisions without attention to the date of decision and governing statute will produce systematic misreadings.
The age of consent to marriage has been particularly volatile historically. Canonical law permitted marriage as early as 12 for girls and 14 for boys. American states varied widely into the twentieth century. Historical family law records will reflect thresholds that would be unlawful today.
The computation of age itself has generated litigation. Bouvier's notes that full age of 21 years is completed on the day preceding the twenty-first anniversary of birth — a rule derived from common law that treated fractions of a day as irrelevant. This birthday-minus-one-day rule appears in English and early American authorities; it may affect how researchers interpret historical capacity determinations made on or near a birthday.
Age of criminal responsibility appears in the corpus most heavily in juvenile justice materials, but also surfaces in older criminal law records where the defendant's age was raised as a defense. The rebuttable presumption structure (incapacity below 7, qualified incapacity 7–14, full liability above 14) is the baseline for interpreting those materials.
In immigration, probate, and benefits contexts, age may need to be established by evidence rather than assumed. The corpus contains significant historical material on age proof — certificates, baptismal records, testimony — that reflects an evidentiary dimension of the concept distinct from the substantive capacity rules.
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Historical Dictionary Support
The historical dictionaries converge on a functional definition: age is the period of life at which law permits persons to do what they were previously prohibited from doing. Bouvier states this most cleanly — "that period of life at which the law allows persons to do acts or discharge functions which for want of years they were prohibited from doing." Burrill echoes the same structure, describing age as "a period of life at which persons become legally competent to do certain acts, or enter into certain contracts, which before they were incompetent to do."
Black's first edition definition is unhelpful as preserved in the source material — the entry appears garbled with agency material — but the second edition treatment is consistent with Bouvier and Burrill.
What the historical dictionaries largely omit: they focus almost entirely on civil capacity (contract, property, marriage) and give limited treatment to criminal responsibility and the infancy defense in tort. The age-of-consent dimension as it applies to sexual offenses is also underrepresented in the standard dictionaries, which reflects both the historical reticence of legal lexicography on the subject and the subsequent statutory explosion in this area. Researchers working on criminal law materials should treat the dictionary entries as a starting point only and consult the corpus's criminal law encyclopedia entries directly.
The historical dictionaries also do not address the modern anti-discrimination dimension of age — the concept that age as a characteristic may be a prohibited basis for adverse action in employment and other regulated contexts. This is entirely a statutory development and postdates the classic dictionaries.
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Jurisdictional Note
Age thresholds vary by jurisdiction and subject matter. Researchers should not assume that the common law age of majority (21) or any modern default (18) applies without checking the governing statute for the relevant time and place. Age of consent to marriage, sexual activity, and medical treatment each have separate statutory bases that may differ within the same jurisdiction.
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Encyclopedia Cross-Reference
Infancy — Age of Criminal Responsibility (The Law Mind Criminal Law Encyclopedia)
Statutory Rape and Age of Consent (The Law Mind Criminal Law Encyclopedia)
Marriage — Capacity to Marry (Age, Consanguinity, Affinity) (The Law Mind Family Law Encyclopedia)
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