Definition
In law, SOLIDITY has a narrow and largely obsolete technical meaning tied to measurement: it refers to the cubic or volumetric content of a body — that is, the three-dimensional space a solid object occupies. In this sense, solidity is essentially synonymous with volume or cubic measure. Bouvier uses the term in the context of French metric measurement, equating the stere (a cubic metre used for measuring firewood) as the base unit for measuring solidity. The term appears in legal instruments, customs documentation, and commercial contracts where the volumetric quantity of goods — particularly bulk commodities like timber, stone, or firewood — must be precisely stated.
This is a term of limited modern legal utility. It surfaces primarily in historical research involving French-origin measurement systems, Louisiana law, early American commercial practice, and international trade documentation from the nineteenth century.
Common Language
Modern common usage (Wiktionary): The state or quality of being solid; moral firmness; validity; truth; certainty; also, the solid contents of a body — its volume or enclosed space.
Historical common usage (Webster's 1913): The state or quality of being solid; density; consistency; strength; soundness; the primary quality of matter by which its particles exclude or resist all others; hardness; massiveness.
Editorial note: Common usage treats "solidity" primarily as an abstract quality — firmness, density, moral dependability. The legal and metrological usage is narrower and more concrete: solidity as a countable, measurable quantity (cubic volume), not merely a property. A researcher encountering "solidity" in a legal instrument should not assume it carries the evaluative or qualitative sense found in ordinary writing. It is a unit-anchored term of measurement, not a characterization.
Common Confusion
SOLIDITY vs. DENSITY vs. VOLUME: These three concepts overlap in ordinary speech but are technically distinct in measurement law. Density refers to mass per unit volume (a ratio). Volume refers to the space occupied, without reference to material. Solidity, as used in the Bouvier tradition, refers specifically to cubic volumetric content as a measured legal quantity — most often expressed in cubic metres or their subdivisions. In historical commercial instruments, confusing these terms can lead to misreading quantity specifications in purchase contracts, timber grants, or customs entries.
Why It Matters in Research
Researchers working in nineteenth-century commercial law, Louisiana civil law materials, or French-influenced American legal documents will encounter "solidity" as a measurement term in contexts where modern sources would simply say "volume" or "cubic measure." The shift in terminology matters: a deed or timber contract specifying a quantity by "solidity" is invoking a precise metrological framework, not using a vague descriptor.
Several research traps apply. First, the French metric system was adopted unevenly across American jurisdictions in the 1800s, meaning the same term could reference different actual units depending on whether a document was drafted under French, Spanish, or American legal conventions — a particular concern in Louisiana, Missouri, and other former French territory states. Second, Bouvier's entry on solidity is embedded within a broader treatment of weights and measures derived from French metrology; researchers who encounter the term without that context may overlook its connection to the stere and the cubic metre system entirely. Third, digitized historical sources frequently produce OCR errors in tables and measurement schedules where "solidity" appears alongside numerical data, degrading searchability.
For researchers tracing solid waste law or environmental regulatory materials, note that "solid" in modern regulatory usage (as in "solid waste" under RCRA) carries an entirely different legal definition — one that is statutory and does not derive from this metrological tradition. The conceptual link is superficial and should not be pursued.
Historical Dictionary Support
Bouvier's is the primary legal dictionary source for this term, and its treatment is compressed: solidity is defined functionally by reference to the stere and its metric subdivisions, with a note distinguishing the measurement of firewood (stere) from other cubic measurements (cubic metre). Bouvier does not elaborate on the term's use in legal instruments or its evidentiary significance in commercial disputes. This is notable — the entry reads more as a reference conversion note than a legal definition, suggesting the term was considered self-explanatory by practitioners working with metric-system documents.
No other major historical legal dictionaries in the Law Mind corpus provide a competing definition. The gap in coverage reflects the term's narrow register: it belonged to the technical vocabulary of weights-and-measures law and commercial practice, not to the doctrinal vocabulary of courts. Researchers should not expect to find judicial elaboration of "solidity" in the way they would find elaboration of terms like "consideration" or "possession."
Jurisdictional Note
The metrological use of "solidity" is most likely to appear in Louisiana legal materials and in federal customs and trade documents from the nineteenth century, reflecting French metric influence. Common-law jurisdictions using imperial measurement systems (cubic feet, cords) would not typically use "solidity" as a legal term of art and are unlikely sources.
Encyclopedia Cross-Reference
For researchers whose interest in "solidity" arises from modern solid waste regulatory contexts rather than historical measurement law, see: environmental_26: RCRA Subtitle D — Solid Waste, Municipal Landfills, and State Programs (The Law Mind Environmental & Energy Law Encyclopedia). Note that the statutory definition of "solid waste" under RCRA is a regulatory construct that departs significantly from any physical or metrological meaning of "solid."