All Saints' Day (November 1st), the Christian holiday honoring all saints; an archaic or poetic term.
From Old English all (all) plus hallow (saint, holy person), contracted from halga. The day was named to commemorate all hallows (saints) together.
Allhallow is the 'all' before Halloween—literally 'all hallows' eve'—so Halloween is literally the night before we celebrate saints, making it the holy day's sarcastic younger sibling.
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