Forty-five
In reference to vinyl records, 45 refers to a type of record by its revolution speed of 45 revolutions per minute. This record disc was usually about 1/2 the circumference of a full record, with a larger central spindle, and contained one song on each side which resulted in calling such records singles.Originally the 45 RPM record was introduced as a longer play version of the 78 RPM discs. The first 45 RPM records were monaural with recordings on both sides of the Disc. Produced in several sizes, the 7" large hole version became the most popular. As stereo recordings became popular in the 1950s, most all of the newer 45 RPM records were recorded in Stereo.
