The wikipedia explanation: An extended play (EP) is a vinyl record, Compact Disc, or music download which contains more music than a single, but is too short to qualify as an LP.
To me Bananas was a single over two sides, although long enough to be considered an extended play.
I'd always been led to believe an EP was a record with four or more tracks. Its all subjective I suppose.
Actually the rules are/were quite strict. EP's were a quite unique format and always considered to be a release in their own right up until 1969 when the powers that be banned them from any official chart release, along with LP's. As a result the last official EP to hit the singles charts (up till then) was Simon & Garfunkels Mrs Robinson EP which was climbing quite happily and had reached #9 when it suddenly vanished from chart listings, despite still selling. LP's had also qualified for the singles chart and according to some listings The Beatles "White Album" was the last LP to actually enter the singles chart.
However to get around this, record companies introduced the "maxi" single which was effectively an EP in all but name. The first of these was Mungo Jerry's In The Summertime and from 1970 to 1975 there was a large amount of these "maxi" singles. Hendrix Voodoo Chile, most of the early T.Rex releases, a lot of the early 1970's re-releases by artists Elvis, Neil Sedaka and even Glen Miller release "maxi" singles which were EP's in everything but name.
In 1975 the powers that be relented and the EP came in from the cold when Status Quo's "Quo Live EP" became the first official EP to chart in 6 years. The EP was back and there was a large number that charted in the following years - Queen, ELO, The Faces, Nazereth, Joe Walsh are a few from the top of my head.
I think the rule was that the EP had to have a seperate name (they became really original - Queen's First EP) and had to be between a certain time in length. It was usually the length of 4 tracks but there were a few that had less tracks, such as Barclay James Harvest Live EP but were longer than the normal single. Some even had a larger number of tracks - Bow Wow Wow charted with Your Cassette Pet EP which had 8 tracks.
What actually happened was that the EP would chart but became commonly known by the lead track. For instance when Motorhead and Girls School charted in 1981 and reached Number 5 with the cover of Please Don't Touch it was in fact the lead track from an EP called The Saint Valentine's Day Massacre EP.
And basically the EP still exists within these boundaries. The most recent EP to chart to my knowledge was by a band called Jamie T with The Chaka Demus EP - made no 23 last year. The waters have become muddied with CD Singles and multi tracks, effectively there can be a crossover but the official EP release will still be "The Whatever EP" by The Whoever
