Definition
Quae est eadem (sometimes rendered "que est eadem" or "quze est eadem" in older typography) is a Latin pleading phrase meaning "which is the same." It appeared in formal common law pleadings — particularly pleas in bar and traverse — as the standard formula by which a defendant or pleader asserted that a trespass, act, or fact described in the plea was identical to the one alleged in the opposing party's declaration, notwithstanding any apparent difference in how the two were described.
The phrase functioned as a legal bridge. Where a declaration described an event in one set of terms and the defendant's plea described what appeared to be a variant of that event, quae est eadem signaled to the court that the pleader was not introducing a new or separate matter — the two descriptions referred to the same underlying act or occurrence. It was an identification device, not a substantive defense in itself.
Common Confusion
The phrase is frequently misread or mistyped in historical sources due to the long-s and ligature conventions of early English printing, which rendered the initial letters of "quae" as "quz," "quze," or "quæ." Researchers encountering "quz est eadem" in a scanned or transcribed document are almost certainly looking at quae est eadem. The variant spellings are typographic artifacts, not distinct legal phrases.
Why It Matters in Research
This term appears almost exclusively in pre-nineteenth-century common law pleading documents and treatises on pleading practice. Researchers working in the Law Mind corpus are most likely to encounter it in:
— Pleading manuals and treatises from the seventeenth through early nineteenth centuries, where it appears as a standard formula phrase requiring no further explanation to contemporary readers.
— Reported cases involving technical pleading challenges, where a party objected that the acts described in the declaration and plea were not, in fact, the same — making the quae est eadem averment the point in dispute.
— Transcriptions of original writs, declarations, and pleas in which OCR or manual transcription has introduced the "quz" variant, creating a search obstacle.
The phrase belongs to the technical vocabulary of common law special pleading, a practice that was largely swept away by the procedural reforms of the nineteenth century — the English Common Law Procedure Acts of 1852 and 1854, and the Field Code reforms in the United States beginning in 1848. After those reforms, the formula became a historical artifact rather than live practice. Any source using quae est eadem as active pleading language almost certainly predates those reforms, which is itself useful dating evidence when working with undated or ambiguously dated sources.
The truncation in the Black's entry — where the source material cuts off mid-sentence — is a common feature of digest-format historical dictionaries and should alert researchers that the full doctrinal context requires consultation of the underlying treatise authority cited: Chitty's Pleading, volume 1.
Historical Dictionary Support
Black's Law Dictionary (2nd Ed.) defines the phrase concisely as words "used for alleging that the trespass or other fact mentioned in the plea is the same as that laid in the declaration, where, from the circumstances, there is an apparent difference between the two," citing Chitty's Pleading. This captures the essential function accurately. The entry reflects the standard treatment: quae est eadem was a pleading of identity, not a pleading of substance.
No additional historical dictionary sources are available for this entry. The phrase is technical enough that it appears more fully discussed in pleading treatises than in general legal dictionaries. Chitty's Pleading and Stephen's Treatise on the Principles of Pleading in Civil Actions are the primary secondary sources for researchers needing the full doctrinal context. Historical dictionaries generally treat the phrase as self-explanatory to readers already versed in special pleading practice — an assumption that does not carry forward to modern researchers.
Jurisdictional Note
The phrase is a feature of English common law pleading practice and was carried into American colonial and early federal courts. Its practical application was never uniform across American jurisdictions, and its disappearance from active use followed different timelines in different states depending on the pace of code pleading adoption.