vapour lock n (General Engineering) a stoppage in a pipe carrying a liquid caused by a bubble of gas, esp such a stoppage caused by vaporization of the petrol in the pipe feeding the carburettor of an internal-combustion engine Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014