Frost (frŏst; 115), n. [OE. frost, forst, AS. forst, frost. fr. freósan to freeze; akin to D. varst, G., OHG., Icel., Dan., & Sw. frost. √18. See Freeze, v. i.] 1. The act of freezing; — applied chiefly to the congelation of water; congelation of fluids.
2. The state or temperature of the air which occasions congelation, or the freezing of water; severe cold or freezing weather.
The third bay comes a frost, a killing frost. Shak.
3. Frozen dew; — called also hoarfrost or white frost.
He scattereth the hoarfrost like ashes. Ps. cxlvii. 16.
4. Coldness or insensibility; severity or rigidity of character.
It was of those moments of intense feeling when the frost of the Scottish people melts like a snow wreath. Sir W. Scott.
Black frost, cold so intense as to freeze vegetation and cause it to turn black, without the formation of hoarfrost. — Frost bearer(Physics), a philosophical instrument illustrating the freezing of water in a vacuum; a cryophorus. — Frost grape(Bot.), an American grape, with very small, acid berries. — Frost lamp, a lamp placed below the oil tube of an Argand lamp to keep the oil limpid on cold nights; — used especially in lighthouses. Knight. — Frost nail, a nail with a sharp head driven into a horse's shoe to keep him from slipping. — Frost smoke, an appearance resembling smoke, caused by congelation of vapor in the atmosphere in time of severe cold.
The brig and the ice round her are covered by a strange black
obscurity: it is the frost smoke of arctic winters. Kane.
— Frost valve, a valve to drain the portion of a pipe, hydrant, pump, etc., where water would be liable to freeze. — Jack Frost, a popular personification of frost.