hoarfrost

Frost Frost (fr[o^]st; 115), n. [OE. frost, forst, AS. forst, frost. fr. fre['o]san to freeze; akin to D. varst, G., OHG., Icel., Dan., & Sw. frost. [root]18. See {Freeze}, v. i.] 1. The act of freezing; -- applied chiefly to the congelation of water; congelation of fluids. [1913 Webster]

2. The state or temperature of the air which occasions congelation, or the freezing of water; severe cold or freezing weather. [1913 Webster]

The third bay comes a frost, a killing frost. --Shak. [1913 Webster]

3. Frozen dew; -- called also {hoarfrost} or {white frost}. [1913 Webster]

He scattereth the hoarfrost like ashes. --Ps. cxlvii. 16. [1913 Webster]

4. Coldness or insensibility; severity or rigidity of character. [R.] [1913 Webster]

It was of those moments of intense feeling when the frost of the Scottish people melts like a snow wreath. --Sir W. Scott. [1913 Webster]

{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. [1913 Webster]

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. [1913 Webster]