The tracks on an album may be related by subject, mood or sound, and may even be designed to express a unified message or tell a story (as in the case of a concept album), or the tracks may simply represent a convenient grouping of recordings made at one time or place, or recordings whose commercial rights are controlled by a single record label. A group of audio tracks is considered to be an album if it has a generally consistent track list (often with minor differences or bonus tracks in different territories, or if the album is "reissued" at different times). An album may be released in a single format, such as on compact disc, or in multiple media formats, ranging from physical ones such as CDs, DVD audio, cassettes and vinyl records, to digital ones such as MP3 and AAC files or streaming audio.

The term "record album" originated from the fact that 78 RPM Phonograph disc records were kept together in a book resembling a photo album. The first collection of records to be called an "album" was Tchaikovsky's Nutcracker Suite, released in April 1909 as a four-disc set by Odeon Records. It retailed for 16 shillings — about £56 (US$101) in 2005 currency.

In 1948, Columbia produced the first 12 inch, 33⅓ RPM microgroove record made of vinyl. With a running time of 23 minutes per side, these new records contained as much music as the old-style album of records and, thus, took on the name "album". For many years, the standard industry format for popular music was an album of twelve songs, originally the number related to payment of composer royalties.

Traditionally, an album ranged in duration from half an hour to an hour, depending on the genre and record label. American pop albums tended to be around a half hour; British pop albums were somewhat longer, often containing 14 songs instead of 11 or 12; jazz albums were longer still; and classical albums were the longest of all. From the dawn of the "album era" (in jazz, about 1954; in rock, about 1962) until about the mid-1960s, albums were often recorded as quickly as possible, sometimes in single sessions. (Prestige Records and Blue Note Records were famous for this; as well, the Beatles' first album and the Byrds' first four albums were all largely recorded in single sessions.)

Vinyl LP records had two sides, each comprising one half of the album. If a pop or rock album contained tracks released separately as commercial singles, these were often traditionally placed in particular positions on the album. A common configuration was to have the album led off by the second and third singles, followed by a ballad. The first single would lead off side 2. In the past, many singles (such as the Beatles' "Hey Jude") did not appear on albums, but others (such as the Beatles' "Come Together" and "Something") were also part of an album released concurrently. Today many commercial albums of music tracks feature one or more singles, which are released separately to radio, TV or the Internet as a way of promoting the album. Albums have also been issued that are compilations of older tracks not originally released together, such as singles not originally found on albums, b-sides of singles, or unfinished "demo" recordings.