Hoar-frost Etymology

Hoar-frost ice crystal growing on a grass stem

Our modern-day English term, "hoar-frost," grew like a fruit from a number of older root languages. By combining the two words' meanings, the term attempts to describe ice crystals that form on the ground or low vegetation, by water vapor sublimating directly into ice without turning to liquid first.

Going back in time, "hoar" grew out of the Middle English, "hore," which came from the Old English, "hār," itself originating from the Proto-Germanic, "hairaz." It is cognate, or related to Old Norse "hārr," Old High German, "hēr," and Old Slavonic, "sěrǔ." The first known use of "hoar" was in 1567, while its roots grew down into the 11th century.


Thick hoar-frost covers opening to squirrel den

Growing forward in time, the Proto-Germanic, "frusta," turned into the Old High German, "frost," then adopted into Old English as "forst" and "frost." Both of these terms were common in English from around 1400 until late in that century, when "frost" was the sole literary survivor. The Old High German "frost" is related to the "frost" of Old Saxon and Old Frisian, and to the "vorst" of Middle Dutch and Dutch. The related term, "freeze," is from the Old English, "freosan," and German / Old High German / Proto-Germanic, "frieren" / "friosan" / "freusanan." 

The root words for hoar led from venerable to grey-haired, morphing into a term that tethers the vision of white ice crystals to that of an old man's beard. The root words for frost led from a generic, "to freeze," to the slightly more specific, "turn to ice."

These days, our winter walks through the woods and over to the frozen creek lead here and there through patches of what one might call, "hore-forst." As we move on through November and the temperature keeps dipping, frost will eventually form on my hoary beard, freezing lips and cheeks until my own English starts sounding rather old.