Sometime during the late 1900s, record companies began to sell sets of 78rpm disc records in hardback ‘albums’. These were much like photograph albums, but with paper sleeves for multiple 10-inch or 12-inch phonograph discs, and they allowed record companies to sell complete musical works such as operas or classical works. The 78 rpm records of the time were only able to contain around 3 minutes of playing time on the 10-inch version, and 5 minutes on the 12-inch versions, so a longer complete work had to be spread across several discs.
Around the same time, empty record albums became available to allow listeners to store and protect their own discs, write information about the contents on an index page, and display the album on bookshelves.
Record albums eventually came to be used to contain compilations by artist, or by genre, in addition to longer works, and a set of 4-5 discs could contain 8-10 songs. Later releases had cover artwork and liner notes.
With the advent of the Long Play microgroove record in 1948 that could hold the same number of songs on a single disc there was no longer a need for record albums containing several discs, and indeed by the late 1950s the 78 rpm disc itself was being phased out. However, the term ‘album’ continues to be used to describe a collection of songs, whatever the format.