For balance and measure, here is Wikipedia's etymology about the word 'hallow:'

Etymology[edit]

Further information: Weoh

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 Germanwīh 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. Theweihs group is cognate to Latin victima, an animal dedicated to the gods and destined to be sacrificed.

In current usage[edit]

Hallow, as a noun, is a synonym of the word saint.^[3][4] In modern English usage, the noun "hallow" appears mostly in the compound Hallowtide, a liturgical season which includes the days of Halloweenand Hallowmas.^[5] Halloween (or Hallowe'en) is a shortened form of "All Hallow Even," meaning "All Hallows' Eve" or "All Saints' Eve."^[6] Hallowmas, the day after Halloween, is shortened from "Hallows'Mass," and is also known as "All Hallows' Day" or "All Saints' Day."^[7]

In legend[edit]

Some important and powerful objects in legends could be referred to as "hallows" because of their function and symbolism.^[8] The Tuatha de Danaan in Ireland possessed the Four Treasures of Ireland which could be interpreted as "hallows": the Spear of Lugh, Stone of Fal, the Sword of Light of Nuada, and The Dagda's Cauldron.

In the modern period, some neo-pagans believe that the four suits in the Rider-Waite Tarot cards deck (swords, wands, pentacles and cups), which are also a representation of the four classical elementsof air, fire, earth and water, are also hallows.

Coronation ceremonies for monarchs still invokes four ritual objects, now represented as the sceptre, sword, ampulla of oil, and crown. Similar objects also appear in Arthurian legends, where the Fisher King is the guardian of four "hallows" representing the four elements: a dish (earth), Arthur's sword Excalibur (air), the Holy Lance or spear, baton, or a magic wand (fire), and the Holy Grail (water).^[9]

Earlier Welsh tradition, as recorded in Trioedd Ynys Prydain, also refers to Thirteen Treasures of the Island of Britain. Symbolically, these could also be interpreted as "hallows", although they are not actually described as such in the medieval Welsh texts.