Inflectional ending of the definite (strong) adj. occurring in early ME: (a) in the gen. and dat. sing. feminine and (b) in the gen. plur. The gen.pl. inflection -er survives in the indef. numeral all in such set phrases as aller best best of all, alder first first of all, alther levest dearest of all, oure aller fader father of us all, their aller soules the souls of all of them.