A machine pistol manufactured by Glock GmbH. It is essentially a select-fire Glock 17 that is very dangerous to fire with one hand and suicide to dual-wield. It completely redefines the term "spray-and-pray".
The robbers' Glock 18s had even the SWAT team diving for cover.
by Zolotros June 15, 2009
A fully-automatic version of the Glock 17. Identical in apperance to Glock 17 except for the Flip lever on the slide used to change fire mode between Semi-Auto and Full-Auto
"The Glock 18 is hard to fire with one hand."
by Richard Gardner January 31, 2006