Torr
The Torr is a unit of pressure. One Torr was originally defined as the pressure exerted by a depth of one millimeter of mercury (mmHg), and then as 1/760 of a standard atmosphere.
Because the standard atmosphere is now a defined quantity in the SI system of units, the Torr is hence defined as exactly 101325 / 760 pascals. Although the torr is still in common use in low-pressure engineering, the pascal is now the recommended unit of pressure.
The torr unit is named after Evangelista Torricelli.
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