A unit of measure of atmospheric pressure equal to 100 newtons per square meter.

a metric unit of pressure equal to 100 pascals or 0.1 kilopascal (kPa). The hectopascal, used almost entirely in measurements of air pressure, is identical to the millibar (mb). The millibar has been used to measure air pressure for many years, but it is not an SI unit. Although meteorologists in various countries use the hectopascal as a kind of alias for the millibar, the natural SI unit for air pressure is the kilopascal.

A unit of pressure equal to a millibar (1 hPa = 1 mb). Abbreviated hPa.