What does frost mean?
Frost is the thin, white layer of ice crystals that forms on exposed surfaces when temperatures fall to freezing point and water vapour in the air solidifies directly into ice. It appears most visibly at dawn on grass, rooftops, car windscreens, and window panes, where it can create delicate, fern-like patterns prized for their beauty. Beyond its physical form, 'frost' also denotes freezing weather conditions generally, particularly when these threaten crops and gardens; gardeners speak grimly of the 'first frost' of autumn and the 'killing frost' that ends the growing season. The word carries connotations of cold, stillness, and winter's arrival, appearing frequently in poetry and seasonal writing. Related terms include 'hoarfrost', named for its feathery, white appearance, and 'rime', a similar deposit formed under foggy conditions.
A thin deposit of ice crystals formed on surfaces when water vapour freezes at or below 0°C.
"By morning, a thick frost had settled over the fields."
Often used uncountably in weather contexts ('frost tonight'), though plural 'frosts' is common in gardening and agricultural talk.
Freezing weather conditions, especially those severe enough to damage or kill plants.
"The late spring frost destroyed half the orchard's blossom."
Plural 'frosts' typically refers to multiple frost events or episodes of freezing weather, especially in gardening and meteorological contexts.
"The region experiences hard frosts well into April."
The Old English word for frost, 'forst' — sometimes written 'frore' — survives in the archaic adjective 'frore', meaning frozen.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of frost
The word 'frost' derives from Old English 'forst' or 'frost', which itself comes from Proto-Germanic '*frostaz', related to the verb root behind 'freeze'. It is thus a native Germanic word rather than a Romance borrowing, shared with cognates such as Old Norse 'frostr'. The related adjective 'frosty' and the verb 'to defrost' are direct derivatives within English.
Related word forms
How frost is actually used
In British English, 'frost' commonly refers both to the icy deposit and to freezing overnight temperatures ('there will be frost tonight'). In American usage, 'frost' as weather is often expressed as 'a freeze' or 'a hard freeze', while 'frost' more specifically denotes the crystalline deposit. 'Killing frost' is an agricultural term for a frost severe enough to destroy vegetation.
Easily confused with frost
Frost is a noun referring to the icy deposit or freezing conditions, while 'frozen' is an adjective or verb form describing the state of being turned to ice.