Definition
FOI has two distinct legal meanings separated by centuries of usage:
1. (French feudal law) Faith; fealty. In the context of French feudalism, foi denoted the oath of fidelity owed by a vassal to a lord — the foundational bond of the feudal relationship. The term is the French equivalent of the Latin fides and the English "fealty," and appears in historical legal texts concerned with the obligations running between lord and tenant.
2. (Modern administrative law) Freedom of Information. An abbreviation for statutory regimes that compel government agencies to disclose public records upon request. In the United States, the principal federal statute is the Freedom of Information Act (5 U.S.C. § 552), enacted in 1966. Many states have parallel statutes, commonly called "sunshine laws" or open records laws, and the abbreviation FOI (or FOIA, adding "Act") is used interchangeably across these regimes. In the United Kingdom, the Freedom of Information Act 2000 creates a comparable framework. The modern FOI framework rests on a presumption of disclosure: records are available unless a specific exemption applies.
Common Confusion
The abbreviation FOI is almost never used in contemporary legal practice to mean faith or fealty. Researchers encountering FOI in a modern legal document, pleading, agency correspondence, or statutory annotation should assume the Freedom of Information sense unless the document is plainly a historical or comparative feudal law source. The collision between the two meanings is a byproduct of historical dictionaries indexing a French feudal term that happens to share initials with a major twentieth-century statutory concept. They are unrelated in origin, substance, and context.
Researchers should also distinguish FOI from FOIA. FOIA typically refers specifically to the federal Freedom of Information Act; FOI is the broader abbreviation used when referring to the concept generally, to state-level statutes, or to foreign equivalents.
Why It Matters in Research
The primary research hazard with FOI is a search that retrieves both meanings without flagging the distinction. A full-text corpus search for "FOI" in a collection that spans historical and modern materials will surface feudal law entries alongside administrative law materials — two entirely different bodies of law with no substantive overlap.
For feudal law research: foi/fealty research should be conducted under the French term directly, or cross-referenced with fidelity, homage, and fealty. The historical dictionaries consistently point to Guyot's Institutes as the authoritative source on the term in French feudal context. Researchers working in that area should treat "FOI" as a pointer to the Guyot citation rather than an independent doctrinal concept.
For modern administrative law research: FOI/FOIA research requires jurisdictional precision. Federal FOIA doctrine (exemptions, Vaughn indices, litigation procedures) differs substantially from state open-records regimes. Many state statutes carry their own abbreviations (Texas has the TPIA; California has the CPRA), so broad FOI searches may miss jurisdiction-specific materials indexed under statute-specific names. Researchers should also track the distinction between records access law (FOI) and open meetings law (sunshine laws) — related but separately codified regimes that are sometimes conflated under the FOI umbrella.
The modern FOI framework has generated a large body of agency guidance, administrative appeals decisions, and federal court doctrine that does not appear in any of the historical dictionaries. None of the four source dictionaries address the administrative law meaning at all.
Historical Dictionary Support
All four source dictionaries — Black's (both editions), Bouvier's, and Burrill's — define FOI identically: faith; fealty, in French feudal law, citing Guyot, Inst. Feod. c. 2. The consistency across all four sources reflects the term's settled and narrow meaning in the nineteenth-century legal lexicon. Burrill adds a cross-reference to FOY, the variant spelling, which is the more common form in older French legal texts.
What the historical dictionaries do not address — and cannot, by date — is the dominant modern usage. The Freedom of Information Act was enacted in 1966, well after all four dictionaries were compiled. Any researcher relying solely on these sources for a definition of FOI will receive accurate but incomplete information: accurate for feudal law contexts, silent on everything the term means in contemporary practice.
Jurisdictional Note
FOI law varies significantly by jurisdiction. The federal FOIA (5 U.S.C. § 552) governs federal agency records and has its own exemption structure and litigation framework. State open-records statutes differ in scope, exemptions, response deadlines, and enforcement mechanisms. The United Kingdom's Freedom of Information Act 2000 operates under a different administrative structure entirely. Researchers should not assume that doctrine developed under one jurisdiction's FOI regime applies in another.