In some ways, the really distinctive thing about disco is implied in its name (taken from the French word 'discotheque' which means something like 'house of discs'): the disc. That is, discos were a relatively new development, reliant on relatively durable and high-fidelity vinyl, and reliant on the technology needed to play those vinyl discs quite loudly in a room (to the extent of competing with a live band with real drums).

In a world of Rolling Stone lists of the greatest rock songs ever, etc, we tend to think that the primary thing about rock'n'roll is its sociocultural and political importance: Bob Dylan singing 'how does it feel?' and the Beatles going g'goo g'joob, etc. But when it comes down to it, most pop music from the rock'n'roll era (1956-onwards) was youth-oriented dance music first and foremost. Look at pretty much any 1960s footage from pop music-oriented TV shows like American Bandstand or Top Of The Pops and you'll see people dancing, often portrayed as being just as prominent as the musical act themselves.

This was especially so for pop music coming from African-American backgrounds, which sank or swam in the pop charts based on its danceability. Note the rise in the 1970s of the Northern Soul scene in the UK, which was, for a while, entirely based around dancing to increasingly-obscure 1960s soul that had 1960s Motown-style four-to-the-floor dance beats (think, say, the big beat of 'Uptight (Everything's Alright)' by Stevie Wonder. Also, and notice the awkward white people dancing to it in the video clip! As rock music increasingly became focused on being a music of self-expression rather than a platform for dancing as the 1960s turned into the 1970s, soul music became increasingly the music for dancing, and vinyl discs played by 'disc jockeys' rather than live bands increasingly became the soundtrack for that dancing.

In this world of dancing to soul music and vinyl discs, in the early 1970s, different nightclubs sprung up catering to clientele with a variety of preferences for what kind of music they would like to dance to - how fast/slow? how straight-ahead/funky? - discos, as these nightclubs came to be called. One particular scene developed in New York discos catering to a predominantly multicultural and LGBT audience, at a time when the Stonewall riots in response to police oppression of gay people were still very recent.

One example of this scene was the prominent disc jockey Nicky Siano's sets at The Gallery, a typical set list of which is captured in a 2004 compilation from Soul Jazz Records titled Soul Jazz Records Presents Nicky Siano's The Gallery. As you can see from the tracklist, the sound of Siano's set lists was not predominantly disco at this point - the genre hadn’t arrived yet, though there were certainly precursors. Instead, Siano’s set lists mostly featured music that had some - but obviously not all - of the elements of the later disco sound. Like disco itself, the set lists were based strongly in 1970s soul music, with elements of the smooth, lush sound of Gamble & Huff's productions for their Philadelphia-based labels, elements of the funk and sophisticated polyrhythms of the African-influenced soul jazz going around at the time, and elements of the Motown big beat.

Such discos like The Gallery appeared to the record companies to be having an effect on record sales. As a result, records that had done well on the dancefloor began to be more likely to be promoted by the record companies; similarly, record companies began to try to make music designed for such dance floors. Thus it was only a matter of time before someone combined all those elements.

Peter Shapiro's book Turn The Beat Around: The Secret History Of Disco identifies a 1973 song by Gamble & Huff's house band M.F.S.B. called 'Love Is The Message' as, essentially, the first song that had all of the important ingredients of disco. Shapiro also talks about how when Siano played it at The Gallery for the first time, the crowd went berserk. After the 1973 release of the Love Is The Message album, and across 1974, disco became very firmly established as a specific musical style within soul music, and indeed pop more generally, with tracks like 'Love's Theme' by the Love Unlimited Orchestra, 'T.S.O.P. (The Sound Of Philadelphia)' by M.F.S.B. 'Rock The Boat' by the Hues Corporation' and 'Kung Fu Fighting' by Carl Douglas having been #1 singles on the US Billboard charts, and 'Dancing Machine' by the Jackson 5 having been a #2 single.