Definition
A tank is an artificial receptacle constructed to contain liquids. In legal usage, the term refers principally to a large basin, cistern, or container — whether of metal, masonry, or other material — designed for the storage or collection of a liquid commodity such as water, oil, or petroleum products.
The term appears most frequently in two legal contexts:
1. OIL AND GAS LAW: A large metal container, typically capable of holding hundreds or thousands of barrels of crude oil or petroleum products, used by producers, refiners, or distributors to store their output. This is the dominant industrial usage that shaped statutory interpretation in oil-producing jurisdictions.
2. WATER AND PROPERTY LAW: An artificial pond, reservoir, or cistern constructed on land to collect and store water for agricultural, domestic, or industrial purposes. In this sense, a tank is distinguished from a natural body of water and may have significance for water rights, riparian disputes, or property boundary descriptions.
Common Language
Modern common usage (Wiktionary): In contemporary English, "tank" functions both as a noun (a large container for liquids or gases; an armored military vehicle) and as a verb meaning to fail or decline sharply, to deliberately lose a competition, or to fill a vehicle with fuel.
Historical common usage (Webster's 1913): Webster's 1913 lists "tank" primarily as a small Indian dry measure averaging 240 grains in weight, and a Bombay weight of 72 grains used for pearls — a meaning now entirely obsolete in both common and legal usage.
The gap between common and legal usage here is directional rather than oppositional. The common noun meaning (a large container for liquid) aligns reasonably well with legal usage, but the legal term excludes the military vehicle sense entirely and has no connection to the modern verb forms. Researchers reading older statutes should not import the weighing-measure sense from Webster's 1913, which was a regional and commercial usage that never entered Anglo-American legal vocabulary.
Common Confusion
Tank (artificial structure) vs. pond or reservoir: In water law and property descriptions, a tank may be confused with a natural or semi-natural pond. The critical distinction in most legal sources is artificiality — a tank is man-made. Whether a structure qualifies as a tank versus a pond or reservoir can affect water rights classifications, easement terms, and ad valorem tax assessments of agricultural improvements.
Why It Matters in Research
The primary research trap with "tank" is contextual: the same word carries meaningfully different legal weight depending on the body of law at issue.
In oil and gas research, statutory and regulatory definitions of "tank" can determine what storage infrastructure is subject to licensing, inspection, bonding, pipeline tariffs, or environmental regulation. Early petroleum-era statutes (late nineteenth and early twentieth centuries) frequently used "tank" without definition, leaving courts to interpret scope. The Bouvier citation to 82 S.W. 1020 reflects this interpretive pattern — courts were asked to decide whether a particular storage structure fell within a statute's reach. Researchers working with oil and gas statutes from Texas, Pennsylvania, Oklahoma, and California should check whether the jurisdiction's enabling legislation or its judicial gloss defined "tank" narrowly (large metal petroleum storage) or broadly (any artificial liquid receptacle).
In water law research, especially in arid and semi-arid western and southern states, "tank" appears in property deeds, ranch surveys, and water-use permits to describe stock tanks and irrigation cisterns. The word may appear in metes-and-bounds descriptions as a landmark. Here, the legal question often turns on whether the tank is a permanent fixture, whether it constitutes a water right appurtenant to land, and who bears maintenance obligations.
Historical sources are sparse on "tank" as a legal term of art. Bouvier's entry is brief and functionally tied to the oil industry context. Researchers should not expect deep common-law doctrine on the word itself — its legal significance is almost entirely statutory and regulatory, and therefore highly jurisdiction- and era-specific.
Historical Dictionary Support
Bouvier's Law Dictionary provides the only historical legal dictionary treatment identified in Law Mind's shelf sources. Bouvier defines the term concisely as "an artificial receptacle for liquids; a large basin or cistern," then pivots immediately to the oil industry context, citing judicial authority for the proposition that statutory use of "tank" refers to the class of large metal petroleum storage structures that had become standard in the oil fields by the early twentieth century.
This is a characteristically narrow Bouvier entry — descriptive rather than doctrinal. It does not address tank in the water law or agricultural context, does not discuss tank as a property fixture, and offers no treatment of regulatory dimensions. Researchers relying on Bouvier alone will find adequate grounding for oil storage disputes but will need to supplement from statutory sources and practice-area treatises for any other context.
No other historical legal dictionary in the Law Mind corpus (Black's, Burrill, Wharton, Rapalje & Lawrence, or Abbott) appears to carry a distinct entry for "tank" as a legal term.
Jurisdictional Note
"Tank" as a regulated structure is treated differently across jurisdictions. Texas and other southern states commonly use the term in water law to describe agricultural stock tanks, which may carry distinct rights and obligations from those attached to reservoirs or ponds. Federal environmental law (notably underground storage tank regulations under RCRA) uses "tank" with a specific statutory definition that may diverge from both the common meaning and historical oil-field usage.
Encyclopedia Cross-Reference
See Law Mind Encyclopedia — Oil and Gas Law (storage infrastructure and statutory definitions); Water Rights and Riparian Law (artificial water structures and property appurtenances).