unit of barometric pressure, by 1910, from milli- + bar (n.4).
word-forming element meaning "thousand; thousandth part (of a metric unit)," from combining form of Latin mille "thousand" (see million).
unit of pressure, coined 1903 from Greek baros "weight," which is related to barys "heavy," from PIE root *gwere- (1) "heavy."
updated on January 19, 2019
atmospheric pressure at sea level is 1013 millibars