Definition of Per accidens:
Contingently, indirectly, by virtue of some chance, circumstance, or happening. Latin for, by happenstance. Opposite of per se.
By chance, by virtue of some incidental or non-essential circumstance; contingently, indirectly.
Of a conversion: by which the quantity of the proposition is changed from universal to particular. Frequently in conversion per accidens (also called conversion by limitation), opposed to simple conversion.
Meaning of Per accidens & Per accidens Definition