SI unit of pressure, Pascal , abbreviated as Pa
1 Pa = 1 N/m2
Some of the other units are atmosphere (atm), bar, kg/cm2 , mm of Hg etc..
1 atm = 1.01325×105 Pa = 1.033 kg/cm2 = 760 mm of Hg
1 bar = 105 Pa
In vacuum related measurements, pressure unit used is torr.
1 torr = 1 mm of Hg