[1] : The Collaborative International Dictionary of English v.0.48

alder \al"der\ addl"d~er, aller \al"ler\ addl"l~er,
   a. from ealra, alra, gen. pl. of as. eal. the d is
   excrescent.
   of all; -- used in composition; as, alderbest, best of all,
   alderwisest, wisest of all. obs. --chaucer.
   1913 webster alderfly

[2] : The Collaborative International Dictionary of English v.0.48

aller \al"ler\, a. for ealra, the as. gen. pl. of eal all.
   same as alder, of all. obs. --chaucer.
   1913 webster
see also:
alder 

Aller >> A Words
Aller, definition of term: Aller
aller_pag1.html