Nomenclature
The symbol (Torr) is spelled exactly the same as the unit (torr), but the letter case differs. The unit is written lower-case, while the symbol of the unit (Torr) is capitalized (as upper-case), as is customary in metric units derived from names. Thus, it is correctly written either way, and is only incorrect when specification is first made that the word is being used as a unit, or else a symbol of the unit, and then the incorrect letter case for the specified use is employed. The torr is frequently coupled with the metric prefix of milli to form millitorr (mTorr) to represent 0.001 Torr. When following the SI convention of not-mixing unit names and unit symbols the torr can be mixed with SI units to form, for example, torr · liters / second (Torr·L/s). The torr is sometimes improperly assigned the symbol "T" which is reserved for the SI unit for tesla.
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