Definition
Per is a Latin preposition meaning "by," "through," "by means of," or "for each," used extensively in legal writing both as a standalone preposition and as a prefix forming compound legal terms and phrases. It appears in four primary functional contexts:
1. As a preposition in Latin compound terms. Per introduces hundreds of standard legal phrases that remain in active use in modern legal writing: per annum (by the year), per capita (by the head, per individual), per curiam (by the court), per se (by itself, inherently), per stirpes (by the root or stock, a method of inheritance distribution), per diem (by the day), and per fraudem (by fraud), among many others. Each compound functions as a distinct legal concept.
2. As a citation signal meaning "by" or "according to." In opinion writing and legal citation, per identifies the authoring judge or justice: "per Story, J." means the passage or rule derives from Justice Story's opinion. This usage treats per as an attribution marker, not a Latin legal term of art.
3. In the historical writ of entry "in the per." In common law real property procedure, a writ of entry sued out against the alienee of the original disseisor, or the heir to whom the disseised land had descended, was said to be brought "in the per." The writ recited that the tenant had no right of entry except "by" (per) the original wrongdoer. This distinguished the per stage from the more remote "per and cui" and "cui in vita" stages of the writ, which addressed more attenuated chains of alienation.
4. As an ordinary English preposition in legal drafting. Courts and practitioners use per in plain English contexts: "per the agreement," "per the statute," "per your instruction." This usage is English, not Latin, though it derives from the same Latin root.
Common Language
Modern common usage (Wiktionary): Wiktionary's primary non-technical definition records per as a neologistic gender-neutral third-person singular pronoun, coordinate with he/she. A secondary meaning captures the ordinary preposition sense: "for each" or "by."
Historical common usage (Webster's 1913): Webster's defines per as "[t]hrough; by means of; through the agency of; by; for; for each," illustrated by per annum, per capita, per curiam, and per cent. Webster's treats per as a Latin word carried intact into English through legal and scientific usage.
The legal meaning is not in conflict with the common English preposition sense — they share the same root and meaning. The gap worth noting is functional: in legal sources, per almost always introduces a term of art or serves as an attribution signal, while in common usage it functions as a simple preposition interchangeable with "for each" or "according to." Researchers should not interpret per in a legal phrase as merely prepositional; the full compound is the unit of meaning.
Common Confusion
Per is sometimes confused with pur (or pour), an Old French preposition also found in English common law writs and compound terms. Pur means "for" in a different sense — purpose or duration — as in pur autre vie (for the life of another) and pur cause de vicinage (because of neighborhood). Anderson's Dictionary explicitly flags this distinction. In historical sources, the two words appear in closely related contexts, and scribal or typographic variation occasionally renders one for the other. Researchers working with writ pleadings or tenure-related materials should confirm whether the source uses per (by/through) or pur (for) before characterizing the legal relationship described.
Why It Matters in Research
Per functions primarily as a gateway term in the Law Mind corpus rather than as a self-contained research destination. Its importance is navigational: understanding per is essential to decoding the Latin phrase vocabulary that pervades legal opinions, pleadings, treatises, and codes from the colonial period through the twentieth century.
Several research traps arise:
First, the per/pur distinction described above is most acute in writs of entry and tenure documents. The per, cui, and post stages of the writ of entry are distinct legal positions, and collapsing them misreads the pleading's description of the chain of title defect. Historical dictionary entries (Bouvier, Black's, Burrill) describe the per stage accurately, but brief sources sometimes omit the full graduated structure.
Second, per curiam requires separate attention. It means "by the court" and is used in two distinct ways: to identify an opinion authored by the court as a whole without an attributed individual author, and to signal a short, summary disposition. These usages have different weight as precedent in different jurisdictions, a distinction that historical dictionaries do not address.
Third, per se is arguably the most consequential per compound in current research. In negligence law, negligence per se is a doctrine converting statutory violations into breaches of duty. In defamation law, defamation per se refers to categories of statements presumptively harmful. In antitrust, per se illegality distinguishes certain restraints from rule-of-reason analysis. These are independent doctrines that share only the modifier; research into one does not substitute for research into another.
Fourth, per stirpes versus per capita distributions remain a persistent source of error in estate and probate research. These are opposing methods of dividing inheritances among descendants, and older wills and intestacy statutes use both terms, sometimes inconsistently. Historical dictionaries define both but rarely explain how they interact when a class includes members of different generations.
Fifth, the attribution usage — per Story, J. — is largely absent from historical dictionaries. Researchers encountering this form in nineteenth- and early twentieth-century legal writing should read it as "according to" or "as stated by," not as invoking a legal term.
Historical Dictionary Support
The historical dictionaries treat per primarily through its most concrete historical application: the writ of entry "in the per." Black's (both editions), Bouvier, and Burrill all reproduce substantially the same passage, tracing the usage to Blackstone's Commentaries at Book III, page 181. This convergence is notable — it reflects how thoroughly the writ of entry framework organized common law property thinking in the period these dictionaries addressed.
Burrill provides the most complete treatment of per's range of prepositional meanings, cataloguing its senses as "by," "through," "in consequence of," "according to," "for," and "during," with examples drawn from Digest 50.16.63. This multi-sense treatment is valuable for decoding historical documents where the precise meaning of per shapes the legal relationship described.
Anderson's is the most practically useful for modern compound-phrase research, listing per annum, per capita, per curiam, and per fraudem as distinct entries cross-referenced within the dictionary.
What the historical dictionaries collectively miss: the modern doctrinal per se compounds (negligence per se, defamation per se, per se antitrust rules) are either absent or treated only in passing. These doctrines developed substantially in twentieth-century caselaw and are not adequately covered by any of the shelf sources. Researchers relying solely on historical dictionaries for per se doctrine will find incomplete guidance.
Encyclopedia Cross-Reference
Negligence Per Se — Torts & Personal Injury Encyclopedia, §8
Defamation Per Se Categories — Torts & Personal Injury Encyclopedia, §123
Physical Takings and Per Se Rules — Constitutional Law Encyclopedia, §66