drop cannon noun billiards a shot in which the first object ball joins or gathers with the cue ball and the other object ball, esp at the top of the table Liberaldictionary.com
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