GC: n

S: http://www.ec.gc.ca/meteo-weather/default.asp?lang=En&n=d9553ab5-1 (last access: 15 July 2015); http://www.bbc.com/weather/2640729 (last access: 15 July 2015).

N: 1. Old English forst, frost “frost, a freezing, frozen precipitation, extreme cold,” from Proto-Germanic *frustaz- “frost”, related to freosan “to freeze,” from suffixed form of PIE *preus– “to freeze; burn”. Both forms of the word were common in English till late 15c.; the triumph of frost may be due to its similarity to the forms in other Germanic languages. A black frost (late 14c.) is one which kills plants (turns them black) but is not accompanied by visible frozen dew.
2. Air temperature equal to or less than the freezing point of water (0°C).
3. Immature wheat is susceptible to frost, which kills the plant and damages the kernels. … Frost damage can range from moderate to severe. The worse it gets, the greater the deterioration in milling and product quality.
4. frost (0°C or 32°F).

S: 1. OED – http://www.etymonline.com/index.php?term=frost (last access: 15 July 2015). 2 & 3. TERMIUMPLUS. 4. METEOTERM/Standard Dictionary of Meteorological Sciences, by G-J. Proulx, Canada (last access: 15 July 2015).

SYN: freezing

S: TERMIUMPLUS

CR: freezing fog, glaze, hail, hailstone, hoar frost, rime, sleet, small hail.