Hallow

To hallow is "to make holy or sacred, to sanctify or consecrate, to venerate". The adjective form "hallowed", as used in "The Lord's Prayer", means holy, consecrated, sacred, or revered. The noun form "hallow", as used in "Hallowtide", is a synonym of the word saint. 
The word 'to hallow' itself in English is now archaic; does not appear other than in the quoted text in the Lord's Prayer in the New Testament ( and ).
Etymology.
The noun is from the Old English adjective "hālig", nominalised as "se hālga" "the holy man". The Gothic word for "holy" is either "hailags" or "weihaba", "weihs". "To hold as holy" or "to become holy" is "weihnan", "to make holy, to sanctify" is "weihan". Holiness or sanctification is "weihiþa". Old English, like Gothic, had a second term of similar meaning, "wēoh" "holy", with a substantive "wīh" or "wīg", Old High German "wīh" or "wīhi" (Middle High German "wîhe", Modern German "Weihe"). The Nordendorf fibula has "wigiþonar", interpreted as "wīgi-þonar" "holy Donar" or "sacred to Donar". Old Norse "vé" is a type of shrine. The "weihs" group is cognate to Latin "victima", an animal dedicated to the gods and destined to be sacrificed.
Usage.
Hallow, as a noun, is a synonym of the word saint. In modern English usage, the noun "hallow" appears mostly in the compound Hallowtide, a liturgical season which includes the days of Halloween and Hallowmas. Halloween (or "Hallowe'en") is a shortened form of "All Hallow Even," meaning "All Hallows' Eve" or "All Saints' Eve." Hallowmas, the day after Halloween, is shortened from "Hallows' Mass," and is also known as "All Hallows' Day" or "All Saints' Day."