First they were called - for about ten minutes allegedly - The Larry Mullen Band, until - as Mullen says - Bono came in and 'blew any chance I had of being in charge.' Not long afterwards the name Feedback was activated (it is rumoured that at the time this was about the only technical music term the band knew the meaning of) and then, in 1977, The Hype.
A year later, in March 1978, band member of the day Dik Evans (brother of David ‘The Edge’ Evans) left the stage in a fit of anger during a concert in Howth. The band stopped playing dull covers on the spot and went straight on to performing their own work, changing the band name to U2 while they were at it.
The band being Irish, it is not entirely unthinkable that an argument had been anticipated, because a friend of Adam Clayton had a list at hand with six possible new band names. Of these six the name U2 disturbed the band the least, and so ...
Since then U2 fans have entered into heated debates about the question what the band name really means.
Some maintain that Berlin's U-Bahn (underground) is credited, line 2 in particular, covering more than 20 kilometers and 29 stations along the way between Pankow and Ruhleben as regular as clockwork.
There are those who find sufficient justification for this band name theory in the fact that the seventh U2 studio album has a partly German title (Achtung Baby).
Another group of U2 fans refers to American spy plane type U-2 (with dash), a specimen of which, flown by Francis Gary Powers, was shot from the sky on 1 May 1960 by the Soviets above Russian territory. Russians who voiced their outrage got an appropriate response from the Americans, convinced as they were that the United States do not have a monopoly on spy flights: U-2! (You too!).
See also: SR-71