A "torr" is a unit of pressure defined as 1/760 of an atmosphere. It is named after the Italian scientist Evangelista Torricelli, who invented the barometer in the 17th century. The torr is commonly used in vacuum measurements and is equivalent to approximately 133.322 pascals. In practical terms, the torr is often used in scientific and engineering applications, particularly in fields like physics and chemistry. It helps quantify low-pressure environments, such as those found in vacuum chambers or during certain laboratory experiments.