Definition
In law, WEIGHT carries two distinct meanings that operate in entirely separate contexts:
1. Physical weight. The measurable heaviness of an object, expressed in standardized units such as pounds, grams, or troy ounces. In commercial, regulatory, and criminal law, weight refers to a quantifiable property of goods, substances, or commodities subject to statutory standards, inspection regimes, or contractual specification.
2. Evidentiary weight. The persuasive force or credibility assigned to a piece of evidence by the factfinder. Evidence may be legally admissible yet carry little weight if it is unreliable, uncorroborated, contradicted, or inherently suspect. Evidentiary weight is distinct from admissibility: a court decides admissibility; the jury (or judge in a bench trial) decides weight. The phrase "weight of the evidence" describes the overall balance of persuasive force across all evidence presented, used to evaluate whether a verdict is against the manifest weight of the evidence on review.
Common Language
Modern common usage (Wiktionary): The downward force an object experiences due to gravity; importance or influence.
Historical common usage (Webster's 1913): The quality of being heavy; that property of bodies by which they tend toward the center of the earth; the quantity of matter as estimated by the balance.
The common language captures physical heaviness and, informally, importance. Legal usage preserves both of these senses but formalizes them into distinct technical domains. In evidentiary law, "weight" is a term of art with a precise procedural consequence: it allocates evaluative authority to the factfinder and insulates that evaluation from appellate second-guessing in a way that "admissibility" does not. A researcher who reads "weight" in a judicial opinion must determine immediately which sense is operative — physical or evidentiary — because the legal rules governing each are entirely different.
Common Confusion
Weight of the evidence vs. sufficiency of the evidence. These are related but distinct standards. Sufficiency asks whether the evidence, viewed most favorably to the verdict, is legally adequate to support a rational factfinder's conclusion — a threshold question. Weight of the evidence asks whether the verdict is against the manifest or great weight of credible evidence — a broader, qualitative review that may acknowledge the verdict clears the sufficiency bar while still being against the weight of the evidence. Courts and older opinions sometimes use these phrases interchangeably, which can distort research. Historical sources are especially unreliable on this distinction.
Physical weight vs. gross weight vs. net weight. Statutes and commercial instruments often specify which measure controls. Gross weight includes packaging, containers, and tare; net weight reflects only the commodity itself. Failure to distinguish these in regulatory or contract research produces errors.
Recognized Forms
/SUBTYPES
Gross weight: The total weight of goods including all packaging, wrapping, and containers.
Net weight: The weight of the commodity itself, excluding all packaging and tare.
Tare weight: The weight of the container or packaging deducted from gross weight to arrive at net weight.
Weight of the evidence: The aggregate persuasive force of all evidence in a case, used in appellate review of jury verdicts.
Legal weight vs. actual weight: In some commodity and pharmaceutical contexts, "legal weight" refers to a weight established or presumed by statute rather than measured.
Why It Matters in Research
Evidentiary weight is one of the most frequently litigated concepts in appellate practice, yet the term appears in historical sources primarily in its physical sense. A researcher scanning nineteenth-century dictionaries for "weight" to understand evidentiary doctrine will find entries dominated by commerce, inspection law, and constitutional powers over standards — not jury evaluation. The evidentiary usage was well established in practice well before it was systematically defined in legal dictionaries.
In corpus research, the physical and evidentiary meanings create a retrieval problem. Full-text searches for "weight" in case law will surface both senses indiscriminately. Researchers should pair "weight" with terms of art: "weight of the evidence," "weight and credibility," or "against the manifest weight" to isolate evidentiary discussions. Regulatory and commercial contexts require different paired terms: "net weight," "gross weight," "standard of weights," or "inspection."
The constitutional dimension matters for historical research. Article I, Section 8 grants Congress power to fix the standard of weights and measures — a power noted by both Anderson and Bouvier — but Congress exercised it incompletely for much of American history. State inspection and weights-and-measures laws filled the gap under the police power. Research into antebellum commercial regulation will encounter this jurisdictional patchwork.
The metric system question also surfaces in historical sources. Bouvier's entry anchors weight to the gramme and the metric standard, reflecting the ongoing nineteenth-century effort to rationalize American weights and measures. A researcher encountering metric references in pre-twentieth-century American legal documents should not assume modern metric adoption; these references typically reflect reform advocacy or specialized scientific and pharmaceutical contexts.
Historical Dictionary Support
Black's (2nd Ed.) treats weight in both senses, opening with the physical definition — "a measure of heaviness or ponderosity" — and adding the metaphorical: "influence, effectiveness, or power to influence judgment or conduct." The entry then pivots immediately to gross weight in a commercial sense, leaving evidentiary weight largely implied. This reflects Black's commercial orientation in that edition.
Anderson's Dictionary gives the most complete treatment of the regulatory dimension, noting Congress's constitutional power, the police power of the states, and the operative systems (avoirdupois and troy). Anderson is the most useful of the shelf sources for understanding the regulatory framework around physical weight in historical practice.
Bouvier's emphasizes the scientific foundation — anchoring weight to the gramme and the properties of water — and the constitutional framework, citing Cooley's Constitutional Limitations on state police power to regulate weights and measures. Bouvier's metric orientation is distinctive among the shelf sources and reflects the dictionary's broader scientific ambition.
Rapalje & Lawrence offers no substantive entry on weight itself; its nearby entries (WEIR, WELFARE, WELL) provide no useful synthesis. For evidentiary weight, the shelf sources as a group are thin. Researchers relying on these dictionaries alone will underestimate the doctrinal complexity of evidentiary weight as it developed through case law.
Jurisdictional Note
Evidentiary weight doctrine is substantially uniform across American jurisdictions in its basic structure, but the standard for appellate review of verdicts as "against the weight of the evidence" varies. Some states permit intermediate appellate courts to reweigh evidence; others confine such review narrowly. The physical standards for weight in commerce are now largely federalized under the Fair Packaging and Labeling Act and related statutes, but state weights-and-measures enforcement remains active.
Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Evidence — Admissibility and Weight; Weights and Measures — Constitutional and Regulatory Framework.