seven-seven

7-7 or 7/7

noun

the 7th of July 2005, the day on which a series of suicide bombings were carried out on the London public transport system by Islamic fundamentalists

Word Origin for seven-seven

C21: by analogy with nine-eleven

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012