Hallow – To sanctify.
Hallowed – To honor as holy.
God used this word in its various forms 37 times in Scripture: 35 times to Israel in their Masoretic Text Old Testament, and 2 times to Israel in their Koine Greek Old Testament (Matthew thru John).
The Catholic Church declared this word to be archaic, and redefined it to mean “holy person or saint”. In the 1300s they coined the word “Hallowmas” and invented a holiday for the assimilation of the Celts; “The mass of the Saints” (like Christmas, the Mass of Christ).
By inventing this holiday, the Celts could join the Christian religion and keep their pagan holiday.
See also Archaic, Christian, Christmas, Consecrate, Halloween, Holy, Honor, Sanctify, Saint