The term revolutions per minute refers to the frequency or rate of speed at which an object orbits or rotates around a fixed axis or another object. It is the number of times each minute that an object spins or moves around its center or another object.
Manufacturers standardized the rotational speeds of phonograph records at 33 1/3, 45 and 78 revolutions per minute and used these numbers to indicate the size and length of a recording. A single, or 45, usually contains one song on each side of a 7-inch disc that spins at a speed of 45 r.p.m., while an LP contains a full album on a 12-inch disc that spins at 33 1/3 rpm.
In contemporary usage, manufacturers of computer drives often express disc speeds as 5400 or 7200 r.p.m.