sub-zero: Meaning and Definition of

sub-ze•ro

Pronunciation: (sub-zēr'ō), [key]
— adj.
  1. indicating or recording lower than zero on some scale, esp. on the Fahrenheit scale: a week of sub-zero temperatures.
  2. characterized by or appropriate for sub-zero temperatures: sub-zero climates; sub-zero clothing for the exploration.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.