There's no back story to the song or much meaning to the title. One of the first songs to show a departure from the shadow of Syd Barrett who'd left in 1968 it's mainly an improvisation on a theme.
Recorded at Abbey Road Studios on November 4th 1968 it would be played live for the next 5 years. Rock had moved further from its roots than ever before.
From the live side of the double album 'Ummagumma'. A miserable YouTube ad a few seconds in on this.
