indicating or recording lower than zero on some scale, especially on the Fahrenheit scale: a week of sub-zero temperatures.
characterized by or appropriate for sub-zero temperatures: sub-zero climates; sub-zero clothing for the exploration.
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How to use sub-zero in a sentence
A runaway teen hitched a ride in the wheel well of a plane that reached 38,000 feet and subzero temperatures.
I found it emotionally and physically draining because sometimes we filmed in subzero conditions in New York.
Silicones for motor insulation and subzero lubricants—used in new glassmaking techniques for myriad products.The Practical Values of Space Exploration | Committee on Science and Astronautics
British Dictionary definitions for subzero
(esp of temperature) lower or less than zero
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012