Definition
A Latin adverbial phrase used in old English legal sources meaning "in arrear" or "behind." Appearing in medieval and early modern legal writing as both aretro and a retro, the term signaled that a sum of money, payment, or obligation was outstanding and unpaid — that is, owed but not yet discharged. It was not a term of art designating a distinct legal action or doctrine but rather a descriptive phrase embedded in pleadings, writs, and judicial records to characterize the status of a debt or obligation.
Common Confusion
Aretro should not be confused with the modern legal term "in arrears," though the two are functionally equivalent. The distinction matters for researchers: aretro appears in Latin-form pleadings and records of the common law courts before the shift to English pleading, while "in arrears" or "arrear" is the natural-language successor used in later English and American practice. Encountering aretro in a source signals you are reading older Latin-register material, which carries its own conventions and interpretive challenges.
Why It Matters in Research
This term is a marker of period and register. When aretro appears in a source, it reliably indicates you are working with Latin-form pleadings, Year Books, or early treatise material — almost certainly pre-18th century and frequently medieval. Its presence is diagnostic: it tells you the document predates or stands within the tradition of Latin pleading in the English common law courts, before Parliamentary reforms and judicial practice gradually shifted legal records into English.
Researchers should be alert to variant spellings. The two-word form a retro appears alongside the fused aretro without any difference in meaning; Black's (2nd ed.) notes both forms. Burrill's citations to Coke's Institutes (2 Inst. 533), Modern Reports (Mod. 5), and Salkeld (2 Salk. 583) locate the term's active use within the 17th-century common law tradition and point toward the kinds of debt and arrears actions — particularly those involving rent and feudal obligations — where the phrase recurs.
Because aretro describes a condition (being behind on a payment) rather than naming a cause of action, researchers will not find it as a standalone entry in most indices or digests. It surfaces inside the text of writs, pleadings, and judicial opinions rather than as a headnote or organizing concept. Boolean and full-text searches in digitized historical corpora will catch it, but only if variant spellings are included in the query.
Historical Dictionary Support
All three source dictionaries agree on the core meaning: aretro means "in arrear" or "behind." Black's (1st ed.) is spare, giving only the definition and the variant spelling. Black's (2nd ed.) is equally brief but confirms both forms. Burrill's is the most useful historically, supplying citations that anchor the term to specific legal contexts — Coke's Second Institutes and the early modern reports — and confirming the phrase quod ei aretro fuit ("which was in arrear to him") as a specimen of actual usage in pleading. None of the dictionaries expand beyond the bare definition, which is appropriate: the term requires no elaboration as a legal concept because it is purely descriptive. What the historical sources collectively miss is any discussion of the transition from aretro to "arrears" in English practice, a shift that occurred gradually as Latin pleading gave way to English.