Definition
In legal usage, DIET carries several distinct meanings that share no obvious connection to one another or to the word's common English sense.
1. Legislative assembly. On the continent of Europe, a formal deliberative assembly of princes, estates, or representatives — functioning as a parliament or congress. The term is applied to bodies such as the historic Diet of the Holy Roman Empire and the Imperial Diet of Japan. In this sense, diet denotes supreme or high-level legislative authority within a sovereign or federal structure.
2. Scottish practice — court sitting. In Scots law, a diet is a sitting of a court. The term describes both the scheduled occasion on which a court convenes and, by extension, particular items of business called for on that occasion.
3. Scottish practice — trial date. A day fixed for the trial of a criminal cause. A diet of trial is the specific sitting at which a criminal case is called and heard. Related uses include the diet of compearance (appearance diet) and the diet of desertion (a sitting at which a case is formally abandoned).
4. Appearance day. More broadly in historical practice, diet referred to a day appointed for a party's appearance before a court or officer — an appearance day in the general procedural sense.
5. Criminal cause prepared for trial. Black's (2nd Ed.) records an additional usage: a criminal cause as it has been prepared and set for trial — referring not just to the date but to the matter itself in its trial-ready state.
Common Language
Modern common usage (Wiktionary): The food and beverage a person or animal consumes; a controlled regimen of food and drink, as to gain or lose weight or influence health; any habitual intake or consumption.
Historical common usage (Webster's 1913): Course of living or nourishment; what is eaten and drunk habitually; food; victuals; fare. Also, a course of food selected with reference to a particular state of health; prescribed allowance of food; regimen prescribed.
The gap here is total. Every legal meaning of diet — legislative assembly, court sitting, trial date, appearance day — is entirely unrelated to the word's common English sense of food or eating regimen. A researcher encountering diet in a historical legal document should suppress the food meaning entirely. Context will almost always resolve which legal sense is intended, but the common meaning offers no foothold and can actively mislead.
Recognized Forms
/SUBTYPES
Diet of compearance: A scheduled appearance before a court; an appearance diet.
Diet of trial: The sitting fixed for hearing a criminal cause.
Diet of desertion: In Scots criminal procedure, the diet at which a prosecution is formally deserted — either pro loco et tempore (temporarily) or simpliciter (permanently, barring retrial).
Diet of diet: Historically, a preliminary procedural hearing used to confirm readiness for a subsequent diet.
Why It Matters in Research
The multi-meaning problem is the central research trap. A source mentioning diet in a European constitutional or diplomatic context almost certainly means legislative assembly. The same word in a Scottish criminal record means court sitting or trial date. These meanings do not overlap and cannot be inferred from the word itself — only from context and jurisdiction.
For researchers working in Scottish legal history, diet is a high-frequency procedural term. Scottish criminal procedure organized case management around diets, and the diet of desertion in particular has significant substantive consequences — permanent desertion operates as an acquittal for double jeopardy purposes. Researchers tracking case outcomes in Scottish records must distinguish among diet types to understand what actually happened to a case.
For researchers working in European constitutional or diplomatic history, diet as legislative assembly appears in primary sources, treaties, and early commentary on comparative government. Blackstone references the term in discussing continental legislative bodies. The connection to parliamentary history makes diet relevant to research tracing the conceptual ancestry of representative assemblies.
The sub-definition recording diet as "a criminal cause as prepared for trial" (Black's 2nd Ed.) is the rarest usage and appears to be more descriptive than a formal term of art. Researchers should treat it as context-dependent and not assume it carries independent procedural significance.
The Latin cognate DIETA (a day's journey, a day's work, a day's expenses) recorded in Rapalje & Lawrence is related but distinct. It appears in feudal and medieval administrative records and should not be conflated with the procedural uses of diet.
Historical Dictionary Support
The historical dictionaries agree on the core meanings but vary in completeness. Rapalje & Lawrence provides the most structured enumeration, listing four distinct senses plus the Latin cognate DIETA. Black's (2nd Ed.) adds the formulation of diet as "a criminal cause as prepared for trial," a usage the other sources omit. Bouvier's treats the legislative assembly meaning as primary and offers little on the Scots procedural senses.
None of the historical sources adequately explains the diet of desertion or its consequences in Scottish criminal procedure — a gap that matters for researchers because the procedural stakes are high. The entries are largely definitional catalogs rather than functional guides, and the Scots procedural uses are underexplained relative to their importance in practice.
Black's (1st Ed.) reference to the quarto die post and appearance day usages, citing Coke on Littleton at 134b–135a, locates diet within the broader vocabulary of medieval and early modern English procedure, though by the time Black's was compiled these English usages were largely historical.
Jurisdictional Note
The legislative assembly sense is a term of European and comparative constitutional law, not domestic American or English usage. The court sitting and trial date senses are Scots law terms with continuing relevance in Scottish criminal procedure. Researchers working in American or English common law sources will rarely encounter diet as a procedural term, and when they do, the usage is almost certainly historical or borrowed.
Encyclopedia Cross-Reference
See Law Mind Encyclopedia — Legislative Assemblies (for the constitutional and comparative government sense)
See Law Mind Encyclopedia — Scottish Court Practice (for diet of trial, diet of desertion, and related procedural uses)