Structure · aka 4/4 kick, four to the floor
Four-on-the-floor
Four-on-the-floor is a drum pattern with a bass-drum hit on every beat of a 4/4 bar. It is the rhythmic foundation of house, techno and trance. Classic trance sits at 128–142 BPM on top of this pattern, usually adding an offbeat open hi-hat and an offbeat bassline to reinforce the pulse.
The pattern is older than dance music itself — it was already standard in disco by the mid-1970s. What classic trance did was speed it up (from disco's ~120 BPM to 138–142 BPM) and strip away everything that could distract from it. The result is a rhythm designed to disappear into the body, so the listener's attention can move to the melody and the arrangement instead. When trance historians say the genre is 'about the melody, not the beat', four-on-the-floor is the beat they mean.