Legal Lexicon & Sources of Authority
A free legal-education surface on what actually counts as law — and what only looks like it. Legal dictionaries are useful, but a dictionary is persuasive reference, not binding law. It records how a word is used; it does not create a right or override a statute or a court’s holding. This is especially worth getting straight if you’ve been told that a line in Black’s Law Dictionary settles a legal question. It doesn’t — and there are better tools, which this surface lays out.
Legal dictionaries — what they are and aren’t
Black’s (1891→today), Bouvier’s (1839, distinctly American), Johnson’s (1755). A dictionary is reference, not law.
Founding-era meaning & originalism
Reading a constitutional word as it was understood when the Constitution was written — with the Heller example.
American common law vs British common law
Reception of English law, Erie (“no federal general common law”), the surviving federal enclaves, and NFIB v. Sebelius.
Persuasive British case law in U.S. courts
Binding vs persuasive authority — e.g. M’Naghten’s Case (1843), the insanity rule adopted across U.S. jurisdictions.
Reception of English law & the earliest American cases
Pre-Revolution British cases and early American law — e.g. Respublica v. De Longchamps (1784).
The Federalist & Anti-Federalist Papers
How courts use them as weighty (but non-binding) evidence of original intent and meaning — and how to cite them.
The American Legal Lexicon
Our own American legal dictionary — 51 terms, each with a plain and a technical definition, sourced.
Dictionary directory
Real, reputable legal dictionaries — Black’s, Bouvier’s, Johnson’s — plus per-country official glossaries.
Using Black’s Law correctly
How the dictionary gets misused as if it were binding law — and what it actually does.
Frequently asked questions
Is Black’s Law Dictionary the law?
No. Black’s Law Dictionary is a reference work — persuasive at most. A dictionary records how a word is used; it does not enact a right, and it cannot override a statute or a court’s ruling. Courts sometimes cite dictionaries as evidence of a word’s meaning, but the binding law is the constitution, statutes, and case law themselves.
What are founding-era dictionaries good for?
They are primary evidence of what a constitutional word MEANT when the Constitution was written and ratified (original public meaning). In District of Columbia v. Heller (2008) the Supreme Court used founding-era dictionaries — including Samuel Johnson’s (1755) and Noah Webster’s (1828) — to fix the meaning of “arms” and “bear arms.”
Does America use British common law?
The states RECEIVED English common law (by reception statutes, with dates and terms that vary by state) and then developed their own American common law. In the federal system, Erie R.R. Co. v. Tompkins (1938) held there is “no federal general common law,” though narrow federal-common-law enclaves survive and federal courts remain the authority on the Constitution and federal statutes.
Is this legal advice?
No. This is free legal education and reference, with every source named. It is not legal advice and not a substitute for a licensed attorney.