Flow measurement is the quantification of bulk fluid or gas movement. Volumetric flow rate is sometimes measured in "standard cubic centimeters per minute" (abbreviation sccm), a unit acceptable for use with SI except that the additional information attached to the unit symbol. The SI standard would be m3/s (with any appropriate prefix, with temperature and pressure specified). The term "standard" indicates that the given flow rate assumes a standard temperature and pressure. Many other similar abbreviations are also in use, such as standard cubic feet per minute or per second. Other units used include gallons (U.S. liquid or imperial) per minute, liters per second, bushels per minute, and acre-feet per day.