Definition
A Latin term from old English legal practice meaning the taxation — that is, the formal assessment and allowance — of costs in a legal proceeding. "Taxatio expensarum" refers to the official process by which a court officer, typically a taxing master or clerk of court, reviewed and approved the costs claimed by a successful litigant to determine which expenses were properly chargeable against the opposing party. It is the Latin procedural designation for what is now called taxation of costs or a bill of costs proceeding.
Why It Matters in Research
This term will appear almost exclusively in pre-modern English legal sources — Year Books, Chancery records, common law pleading manuals, and treatises predating the nineteenth-century procedural reforms in England. Researchers encountering it in primary sources should understand it as functionally equivalent to the modern "taxation of costs" procedure, not as a substantive doctrine.
The critical research trap is terminological drift. After the Judicature Acts of 1873–1875 and the subsequent procedural consolidations, Latin procedural terminology fell out of standard legal usage in English courts. American practice shed this Latin form even earlier. A researcher searching Law Mind's corpus for costs-related procedure should not rely on "taxatio expensarum" as a live search term for materials after the mid-nineteenth century; the underlying concept survives robustly, but the label does not.
Because costs taxation was historically a separate procedural step with its own officers and rules — distinct from the underlying judgment — sources treating taxatio expensarum may appear in sections of treatises devoted to practice and procedure rather than substantive law. Look for it alongside discussions of bills of costs, the office of the taxing master, and the distinction between party-and-party costs and solicitor-and-client costs.
Historical Dictionary Support
Both Black's Law Dictionary (1st and 2nd editions) provide identical, minimal entries: "In old English practice. Taxation of costs." The 1st edition attributes the usage to Wharton, referencing Francis Wharton's Law Lexicon, which similarly treats the term as a period piece of English practice vocabulary. Neither edition elaborates on the procedure itself, treating the Latin phrase as a simple vernacular translation problem rather than a substantive legal concept requiring analysis.
This brevity reflects the term's status at the time of Black's writing: it was already archaic, preserved in the dictionary primarily for readers encountering it in older English authorities. What the historical dictionaries do not address — and what researchers should supply from other sources — is the procedural mechanics of costs taxation itself, the role of the taxing master, and the standards governing which expenses were allowable. For that substance, contemporaneous English practice treatises are the appropriate source.
Jurisdictional Note
The term is specific to historical English common law practice. It does not appear as operative terminology in American courts, which adopted vernacular procedural language earlier. Researchers working in colonial American legal materials may encounter it in courts modeling themselves closely on English Chancery or common law practice, but it is uncommon even there.