Definition
CIL is an abbreviation with no single fixed legal meaning. In legal research contexts, it most commonly appears as a shorthand for one of the following:
1. CONSEIL DE FAMILLE (Council of Family / Council of Kin). In Louisiana civil law practice, CIL historically referred to the conseil de famille — a formal assembly convened by judicial order, consisting of the minor's relatives or, in their absence, friends, to deliberate on matters of guardianship and the administration of a minor's property. Participants were sworn and presided over by a justice. The institution derived from French civil law and was a distinctive feature of Louisiana's civilian legal tradition.
2. CUSTOMARY INTERNATIONAL LAW. In modern international law scholarship and practice, CIL is the dominant abbreviation for Customary International Law — the body of unwritten international legal norms formed through consistent state practice accompanied by opinio juris (the belief that such practice is legally obligatory). CIL stands alongside treaty law as one of the two primary sources of public international law.
3. CLERK (historical abbreviation). Some historical English legal records used CIL or similar contractions as a scribal shorthand in plea rolls and year books. Researchers encountering the abbreviation in early English legal manuscripts should treat it as potentially contextual rather than standardized.
Common Confusion
The abbreviation CIL is not self-defining and has been used inconsistently across legal fields, time periods, and jurisdictions. A researcher encountering CIL in a 19th-century Louisiana document is almost certainly reading a reference to the conseil de famille procedure. The same abbreviation in a 20th- or 21st-century international law text almost certainly means Customary International Law. Confusing the two produces serious misreading. The technological meaning — Common Intermediate Language, a Microsoft .NET specification — is irrelevant to legal research contexts and can be disregarded unless the document concerns intellectual property or technology law.
Why It Matters in Research
The critical research trap with CIL is context-dependence. The abbreviation carries no inherent meaning without the surrounding document, time period, and legal field.
For Louisiana civil law research: The conseil de famille procedure is deeply embedded in Louisiana's 19th-century guardianship records, succession proceedings, and notarial archives. Researchers working in Louisiana parish records before the mid-20th century will encounter CIL as a procedural marker indicating that a family council was convened. This institution was formally abolished or significantly restructured as Louisiana modernized its guardianship law; researchers should not assume the procedure functions the same way across different eras of Louisiana law.
For international law research: CIL as Customary International Law is ubiquitous in post-World War II scholarship, ICJ opinions, Restatement (Third and Fourth) of Foreign Relations Law commentary, and academic journals. The two-element test — consistent state practice plus opinio juris — is contested in application even when the framework is agreed upon. Researchers should be alert to debates about whether CIL can bind non-consenting states (the persistent objector doctrine) and about the relationship between treaty law and CIL when they overlap or conflict.
For historical English legal manuscripts: Burrill's entry referencing scribal Latin abbreviations (L. Fr., Bracton, Kelham's Year Books) suggests that CIL-type contractions in early records require paleographic and contextual resolution rather than dictionary lookup.
Historical Dictionary Support
The three source dictionaries present sharply divergent material, none of which directly defines CIL as a standalone term. This is itself informative: CIL was treated in the 19th century as an abbreviation pointing elsewhere rather than a term with its own legal content.
Bouvier refers the reader to CLERK OF THE PEACE, suggesting the abbreviation appeared in that context in some editions or indexing systems. This reference is not further developed and should be treated as a cross-reference artifact rather than a substantive definition.
Rapalje & Lawrence contains the most substantive material, describing the Louisiana conseil de famille with reasonable precision: a judicially convoked meeting of relatives or friends of a minor, sworn and presided over by a justice, concerned with guardianship and property administration. The entry's text as preserved is fragmentary, with apparent printing corruption interrupting a related entry (likely on FARLEY or a heriot-related term). Researchers should treat the Rapalje & Lawrence description as useful background on the Louisiana institution but should verify procedural details against Louisiana civil codes of the relevant period.
Burrill's entry is clearly misaligned — the text concerns ancient English borough towns mentioned by Bracton and preserved (with exceptions) into the Municipal Corporations Act (5 & 6 Will. IV, c. 76), not any term that begins with CIL. This appears to be a cross-reference or indexing artifact in the source dictionary rather than a substantive CIL entry.
None of the historical dictionaries address Customary International Law, which is expected: CIL in that sense is a 20th-century usage that postdates these sources.
Jurisdictional Note
The conseil de famille meaning of CIL is specific to Louisiana and jurisdictions with direct French civil law inheritance. Customary International Law as CIL is a term of international law, not domestic U.S. law, though it is incorporated into U.S. law through the foreign relations framework and Restatement doctrine.