Definition
A term with two related but distinct legal meanings, both rooted in the concept of equality of standing.
1. In feudal law: The vassals of a lord who sat in his court as judges of disputes among their fellow vassals. They were called peers because each was the equal of the others — of the same rank and condition — and thus qualified to judge one another. This is the ancestor of the modern jury concept.
2. In English constitutional law: The nobility of Great Britain holding seats in the House of Lords — specifically lords temporal, comprising dukes, marquises, earls, viscounts, and barons. In this sense, "peer" denotes a titled noble of the realm.
3. In criminal and constitutional law (the sense most relevant to American legal research): Equals in rank and station. This is the operative meaning in the phrase "trial by a jury of his peers," drawn from Magna Carta's guarantee that no free man shall be imprisoned or dispossessed except by the lawful judgment of his peers. In modern American law, this has evolved to mean fellow citizens generally — not social equals in any class-based sense.
Common Language
Modern common usage (Wiktionary): A section of the British Houses of Parliament; the House of Lords, also called the House of Peers.
Historical common usage (Webster's 1913): One of the same rank, quality, endowments, or character; an equal; a match; a mate. Also, a nobleman; a member of one of the five degrees of the British nobility.
The common usage tracks the noble-class meaning closely, which can mislead researchers. When "peers" appears in constitutional texts, founding-era legal arguments, or jury-right discussions, it carries the equality meaning — not the aristocratic one. A researcher who reads "judgment of peers" through the lens of English peerage misreads the guarantee entirely.
Common Confusion
The two meanings pull in opposite directions. In English law, peers are specifically the nobility — a narrow, privileged class. In the constitutional guarantee of trial by peers, the term means the opposite of a privileged class: it means one's equals, ordinary members of the community. American law inherited the phrase from Magna Carta but stripped out its class-stratified English meaning. Conflating these meanings produces the misconception that the Sixth Amendment or due process guarantees a jury of one's literal social equals, a theory courts have consistently rejected.
Why It Matters in Research
Researchers encounter "peers" in at least three distinct corpus contexts, and the applicable meaning shifts in each.
In feudal law materials, peers appears as a structural description of how manorial and feudal courts functioned — vassals judging vassals. This is important background for understanding the historical origins of jury trial.
In English constitutional history and sources touching Magna Carta, peers carries double freight: it referred to barons in 1215 (a class-specific guarantee), but American courts and commentators progressively universalized it into a guarantee of citizen juries without regard to class. Researchers using pre-Revolutionary English sources must be alert to this transformation.
In modern American procedural law, the phrase "jury of one's peers" is largely ceremonial — courts have held that it requires only a jury drawn from the community without systematic exclusion, not a jury matched to the defendant's demographic profile. Sources from different periods will reflect different stages of this evolution.
A separate and growing usage appears in evidence and procedure materials: "peer review" in the Daubert framework uses "peers" in the scientific-community sense — review by qualified experts in the same field. This is not a legal term of art derived from the feudal or constitutional tradition, but researchers moving between jury-right materials and expert testimony materials should not conflate the two.
Watch for the Bouvier's entry in this corpus — the source material provided under Bouvier's actually contains the entry for REPRIEVE, not PEERS. This appears to be a corpus indexing error. Do not rely on Bouvier's as a source for this term without independent verification.
Historical Dictionary Support
Black's (both editions) and Burrill's agree on the core feudal meaning and the constitutional application. Burrill adds the most useful historical scaffolding, citing Montesquieu's Esprit des Lois and Magna Carta chapter 29, and explicitly tracing the line from feudal peer-judgment to trial by jury. This lineage is well-supported and uncontroversial among the historical dictionaries.
What the historical dictionaries understate: the American transformation of the term. They present the feudal and English noble-class meanings as primary and treat the jury-of-equals meaning as derivative. For American legal research, the priority is reversed. The historical sources also do not address the modern scientific "peer review" usage at all, which is entirely a twentieth-century development.
The Bouvier's entry in the source material is misfiled (it contains REPRIEVE) and contributes nothing to this term.
Jurisdictional Note
In England, "peer" retains its aristocratic meaning — a holder of a hereditary or life peerage with rights in the House of Lords. In the United States, that meaning is constitutionally foreign; the guarantee of trial by jury has been interpreted without reference to social class or rank. Researchers using English treatises or parliamentary materials in an American legal context must manually adjust for this divergence.
Encyclopedia Cross-Reference
civpro_171: Expert Testimony — Daubert Factors (Testability, Peer Review, Error Rate, General Acceptance) (The Law Mind Civil Procedure & Evidence Encyclopedia) — relevant for the "peer review" usage in expert testimony admissibility analysis, which is distinct from the constitutional meaning of peers.