Hoarfrost
/ˈhɔːr.frɒst/noun
A white coating of ice crystals formed on cold surfaces by direct deposition of water vapor.
Did you know?The first element, hoar, comes from Old English hār meaning “gray, white, or aged,” so hoarfrost literally names frost by its ghostly color, not by temperature alone.
Etymological Timeline
Proto-Indo-European
PIE
*ḱerh₂-
“to become gray or old”
Old English
OE
hār
“gray, white, aged, venerable”
Old English
OE
hār-frost
“hoary frost; frost that whitens surfaces”
Middle English
ME
horfrost / hoarfrost
“white frost, rime”
Modern English
English
hoarfrost
“a white coating of ice crystals on cold surfaces”