Definition
A Latin term from Roman civil law meaning, literally, a turning away or averting. In legal usage, aversio denotes a mode of contracting in which a thing is sold or let in gross — that is, as a whole or in bulk — rather than by individual units, parts, or measurements. Two primary applications appear in the historical sources:
1. Sale in gross (per aversionem): A sale of a quantity or collection of goods as a single undivided whole, without itemization or measurement of component parts. The price is fixed for the entirety, not calculated by weight, count, or measure.
2. Letting of property in bulk: The leasing of a house or building as a whole, rather than room by room or chamber by chamber. Kent's Commentaries use aversio in this sense to distinguish whole-property lettings from piecemeal arrangements.
A subsidiary usage appears in Kent's treatment of insurance law — aversio periculi, meaning a turning away of peril — as a characterization of the fundamental purpose of an insurance contract.
Common Confusion
Aversio is sometimes loosely equated with any lump-sum transaction, but its specific civil law force is narrower: it describes a structural feature of how a subject matter is defined and sold (in undivided totality), not merely how a price is expressed. The phrase per aversionem is the more commonly encountered form in legal texts; aversio itself is the root noun from which that phrase derives.
Why It Matters in Research
Researchers will encounter aversio most often not as a standalone term but embedded in the phrase per aversionem, which appears in civil law treatises, Scottish law sources, and American commentary derived from Kent. When tracing doctrine on sales of goods, bulk sales, or leasehold arrangements in sources predating the Uniform Commercial Code, this civil law vocabulary frequently surfaces without translation.
The insurance meaning — aversio periculi — is historically significant. Kent's Commentaries treat it as a shorthand for the conceptual essence of insurance (diversion of risk from insured to insurer), and early American insurance law commentary draws on this framing. Researchers working on the theoretical foundations of insurance contract doctrine should note this usage alongside the commercial sale meaning; the two are entirely distinct despite sharing the same root term.
Historical sources will not always signal which sense of aversio is intended. Context — whether the surrounding discussion concerns sales of goods, leases, or insurance — is the only reliable guide.
Historical Dictionary Support
The three source dictionaries agree on substance but vary in depth. Black's (both editions) and Burrill's all define aversio as an averting or turning away applied to sale in gross or bulk. Burrill adds the most etymological detail, tracing avertere from a (from) and vertere (to turn), and directs readers to the dictionaries of Brissonius and Calvin for full treatment — references that signal the term's deep roots in continental civil law scholarship. Researchers needing the full philological and doctrinal history should consult those sources directly; the Anglo-American dictionaries summarize rather than develop them.
Black's (2nd Ed.) is the only source among the three to include the insurance sense (aversio periculi), citing Kent's Commentaries, Vol. 3. This makes the 2nd edition the more complete reference for researchers encountering the term in insurance history contexts.
The citation to 4 Kent, Comm. 517 (for the leasing sense) appears in both Black's editions and provides a reliable anchor for further research. Burrill omits the leasing sense and the insurance sense entirely, limiting his entry to the commercial sale meaning.
Jurisdictional Note
Aversio is a civil law term with no direct common law equivalent. Its relevance in American legal sources is largely confined to jurisdictions with civil law heritage (particularly Louisiana) and to academic and treatise discussion of Roman and continental commercial law principles. In most common law jurisdictions, the concept it describes — sale or letting in bulk — is handled without Roman terminology.
Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Per Aversionem; Bulk Sales; Insurance Contract (Historical Foundations).