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

allhallow \all`hal"low\, allhallows \all`hal"lows\, n.
   1. all the saints in heaven. obs.
      1913 webster

   2. all saints' day, november 1st. archaic
      1913 webster

[2] : WordNet (r) 2.0

allhallows
     n : a christian feast day honoring all the saints; first
         observed in 835 syn: all saints' day, november 1, hallowmas,
          hallowmass
see also:
all saints' day november 1 hallowmas hallowmass 

Allhallows >> A Words
Allhallows, definition of term: Allhallows
allhallows_pag1.html

Allhallows Eve >> A Words
Allhallows Eve, definition of term: Allhallows Eve
allhallows+eve_pag1.html