Inherited from Middle French -on, from Old French -on, a blending of Latin -ōnem (accusative singular of -ō, masculine appellative suffix), Frankish *-on (accusative of *-ō, ending of masculine weak declension nouns), Frankish *-īn (diminutive suffix), and *-ing (diminutive suffix for animals, via -enc, -enz). Some also descend from the Celtic singulative *-onos, such as mouton.