Definition
In old English legal usage, costus is a Latin term meaning "cost" or "costs" — that is, the expenses, charges, or fees incurred in the course of legal proceedings. The term appears in medieval English statutory and court records as part of the Latin legal vocabulary common before the full transition to English in legal documents. It is most closely associated with the Statute of Westminster II (1285), which addressed the recovery of costs in litigation.
Common Language
Modern common usage (Wiktionary): A perennial tropical herbaceous plant of the genus Costus (family Costaceae); also specifically Saussurea costus, a flowering plant of the Himalayas valued historically for its aromatic root.
Historical common usage (Webster's 1913): Costus appears in botanical and pharmacological contexts as an aromatic plant root of Eastern origin, valued in ancient and medieval trade as a spice and medicinal substance.
The gap here is total. The botanical costus and the legal costus are unrelated words that happen to share a Latin spelling. A researcher encountering costus in a legal record, plea roll, or statute is reading a procedural term about litigation expenses — not a reference to any plant or commodity. Confusion is unlikely in context but worth flagging for researchers working across medieval trade records and legal records simultaneously, where both senses could theoretically appear in proximate documents.
Why It Matters in Research
Researchers working in pre-modern English legal records — Year Books, plea rolls, parliamentary rolls, or the statutes of Edward I — will encounter costus as routine procedural vocabulary. Its importance lies less in its definition, which is simple, than in its role as a marker of the procedural history of costs recovery in English law.
The reference in Burrill to Statute of Westminster II, chapter 46 is the anchor point. That provision established a right to recover costs for plaintiffs who prevailed in certain actions, representing an early codification of what would become a substantial and contested body of costs law. A researcher tracing the history of litigation costs in English law should treat costus in primary sources as a direct antecedent to later English costs doctrine and modern fee-shifting rules.
Caution: Because costus appears in Latin-language legal records, it may be transliterated or translated inconsistently across different editions, calendars, and abstracts of historical records. Some printed calendars of medieval plea rolls render costus directly into English as "costs" without flagging the original Latin. If you are working from a calendar or abstract rather than from the original Latin text, the Latin term may be invisible to you. This matters when tracking exact statutory or judicial language.
The term also illustrates a broader indexing challenge: Law Mind's historical dictionary sources use Latin legal terms as headwords, meaning that the English concept of "costs" and the Latin headword costus may not cross-reference cleanly in all search contexts. Researchers should query both.
Historical Dictionary Support
Burrill's Law Dictionary is the sole source in the Law Mind corpus carrying this entry. Burrill's treatment is brief: it identifies costus as old English law Latin for "cost," cites Statute of Westminster II, chapter 46, and moves on. No further elaboration is offered.
This brevity is itself informative. By Burrill's era (mid-nineteenth century), costus as a live legal term had long since given way to the English "costs," and Burrill's entry functions essentially as a glossary note for researchers reading old Latin records rather than as a definition of a working legal concept.
Other historical law dictionaries in general circulation — Jacob's Law Dictionary, Tomlin's Law Dictionary — address "costs" as a substantive English legal concept at length, but do not necessarily preserve the Latin headword costus. Burrill's value here is precisely in bridging the Latin record to the English doctrinal tradition. Researchers should consult those English-language entries on "costs" for substantive doctrine and reserve Burrill's costus entry for its function as a Latin glossary reference.