A millibar (mb) is 1/1000th of a bar, a unit for measurement of pressure. It is not an SI unit of measure. The SI unit is the pascal (Pa), with 1 millibar = 100 pascals.
The millibar unit was introduced by Sir Napier Shaw in 1909, and internationally adopted in 1929.
Unicode has a symbol for "mb": (㏔).
