Definition
Materials, in law, refers to physical substances or matter used, furnished, or intended for use in the construction, manufacture, or completion of a structure, vessel, or mechanical product. The term carries distinct significance across several legal contexts:
1. Construction and mechanics' lien law. Materials are the raw or finished physical inputs supplied for the erection of a building, ship, or other structure—lumber, steel, brick, fixtures, and the like. A supplier of materials who is not paid may acquire a lien against the improved property under mechanics' lien statutes, distinct from the labor claims of workers.
2. Property and bailment law. When materials are furnished to a workman under a contract for labor and services only, general property (ownership) in the materials remains with the person who supplied them (the bailor). Where the arrangement is instead a sale of materials, ownership passes to the buyer. The distinction controls remedies: a bailor whose materials are converted may pursue trover; a seller's remedy sounds in contract.
3. Federal criminal law — material support. "Material support or resources" is a statutory term of art under 18 U.S.C. § 2339A and § 2339B, defined to include tangible goods, property, services, personnel, transportation, and financial instruments provided to designated foreign terrorist organizations or in support of terrorism. This usage is wholly separate from the construction-law meaning and carries First Amendment implications.
4. Evidence and procedure — materiality. Although "materials" in the plural often appears informally in litigation to denote documents and things produced in discovery, this usage overlaps with but is not identical to the concept of materiality (the quality of being relevant and significant to the outcome of a proceeding). That concept is treated separately under MATERIAL and MATERIALITY.
---
Common Language
Modern common usage (Wiktionary): Plural of "material" — substances or components from which things are made, or, broadly, supplies needed for any activity.
Historical common usage (Webster's 1913): Substances out of which anything is made or composed; also, tools, supplies, and equipment assembled for a purpose.
The legal meaning tracks the ordinary sense closely in construction contexts but diverges sharply in federal criminal law, where "material support" encompasses intangible services and personnel in addition to physical goods. A researcher moving between a nineteenth-century mechanics' lien case and a modern counterterrorism prosecution will find the same word doing fundamentally different work.
---
Common Confusion
Materials and materiality are routinely conflated in casual legal writing. Materials (noun, plural) denotes actual physical or statutory inputs. Materiality is a legal quality — the property of being significant enough to affect a decision, verdict, or contract. A supplier furnishes materials; an omitted fact possesses (or lacks) materiality. In discovery practice, attorneys speak of "case materials" when they mean documents generally, which can blur both concepts. Keep them distinct in index and keyword searches across the corpus.
---
Why It Matters in Research
The construction-law meaning dominates in nineteenth- and early twentieth-century sources. Mechanics' lien cases, shipbuilding disputes, and building contract litigation all turn on whether particular items qualify as "materials" supplied — the 71 Pa. 293 citation (Moyer v. Pennsylvania Slate Co.) referenced by both editions of Black's and by Bouvier concerns exactly this question. Researchers working in that case law should track whether a jurisdiction's lien statute defines materials narrowly (only physical components incorporated into a structure) or broadly (equipment and consumables used during construction).
The bailment dimension — that title to materials does not pass unless the contract is a sale — connects directly to trover and conversion doctrine. Pre-UCC sources treat this distinction with care; post-UCC sources largely address it through Article 2 sale versus service-contract analysis. Researchers should not assume consistency across that divide.
The federal material-support meaning is entirely a late-twentieth-century development. It appears nowhere in the historical dictionaries and has been substantially shaped by constitutional litigation over whether it reaches protected speech and association. Researchers in that area need the Criminal Law and Constitutional Law encyclopedia entries; the construction-law dictionary sources are irrelevant.
For discovery and litigation-file contexts, "materials" as a term of art rarely appears in formal statutes or rules — Federal Rule of Civil Procedure 26 uses "documents and things" or "electronically stored information" — so searches relying solely on "materials" will undercount relevant authority.
---
Historical Dictionary Support
All three historical sources agree on the core definition: physical matter furnished for construction or mechanical manufacture. Black's 1st and 2nd editions are nearly verbatim, both citing Moyer v. Pennsylvania Slate Co. Bouvier adds two substantive refinements absent from Black's. First, Bouvier distinguishes the bailment scenario (property remains in the bailor under a labor contract) from the sale scenario — a distinction with direct remedial consequences that Black's omits. Second, Bouvier cross-references Bailment, Mandate, Trover, and Trespass, flagging the remedial tree a claimant might pursue. Researchers relying solely on Black's would miss this ownership-and-remedy dimension.
None of the historical sources anticipates the federal criminal law usage, nor do they address materiality in the evidence sense — a reminder that these entries are products of their era and are complete only within the construction and property law universe they inhabited.
---
Jurisdictional Note
Mechanics' lien statutes define "materials" by state, and the differences are real. Some states require that materials be actually incorporated into the structure to support a lien; others extend protection to materials delivered to the job site even if not yet incorporated. Researchers working multi-state construction disputes should treat the historical sources as background only and verify the operative statutory definition in the relevant jurisdiction.
---
Encyclopedia Cross-Reference
Contracts & Commercial Law Encyclopedia — "Performance: Material Breach vs. Minor Breach": For the separate but related doctrine of material breach, which uses "material" as a qualitative legal standard rather than a reference to physical inputs.
Criminal Law Encyclopedia — "Terrorism Offenses and Material Support (18 USC 2339)": Full treatment of the federal statutory definition and its application.
Constitutional Law Encyclopedia — "Terrorism, Material Support Statutes, and First Amendment Limits": First Amendment constraints on the material-support statutes, including the distinction between speech and tangible support.
---