The 12 inch, 33 and 1/3 rpm long playing vinyl disc (called an "L.P.") suceeded the 10 inch, 78 rpm shellac disc during the early 1950s as the standard format for music reproduction. Through the 1980s the L.P. remained the prime type of recorded media available commercially, it was more or less completely replaced by digital Compact Discs during the 1990s
Collections of "78s" were kept in multi-sleeved folios not unlike photo albums. A single L.P. would typically contain a whole album's worth of "78s," so recordings in this new format were also referred to as "albums" even though an L.P.'s large carboard packaging is nothing like an album in design.
From the late 1940s on, all long-playing music recordings, including today's CDs and digital download collections, have been referred to as albums. In a sense we've come full circle with multi-CD sets frequently being packaged in something like miniature versions of the original 78 rpm record albums.
E105-LPs (Recent Donations)
E205-LPs (Older Records)
LP informational links:
An overview of several phonographic types
Afrika Islam biography, and a video of his: Viva La Revolucion
Image above, "Tone B Am Busy," by Joe Conzo, photographer, circa 1980