Barrage balloons: Small dirigibles were tethered at low altitude from ships and on the beachheads; the object was to discourage low-level strafing by enemy planes, few of which appeared on D-Day.
D-Day: Army lingo for ``the date of a planned action,'' used for planning purposes when a day has not been fixed or must remain secret. It has become inextricably linked to the Normandy invasion. ``D-Day'' and ``H-Hour'' (the hour of attack) came into use in World War I.
DUKWs: Large (2.5-ton) six-wheel-drive amphibious trucks. ``D'' stood for the date of design (1942), U for amphibious, K for all-wheel drive, and W for the axle configuration (dual rear). Soldiers called them ``Ducks.''
Hobart's Funnies: Specialty tanks developed by Gen. Percy Hobart of the 79th Armoured Division. They included duplex-drive tanks, or DDs, that were fitted with propellers and air-filled canvas screens around their hulls so they could float. ``The Crab'' had a rotating drum and chain flails that could beat a path through a mine field; another tank carried a 40-foot bridge that could be unfolded across antitank ditches. Carpet-laying tanks unrolled matting over the sand for a roadway.
LCI, LCM, LCT, LCVP, LST: Acronyms for, respectively: Landing Craft, Infantry; Landing Craft, Medium; Landing Craft, Tank; Landing Craft, Vehicle and Personnel; Landing Ship, Tank. The LCVP and LCT bore the stamp of Andrew Higgins, the Louisiana-based shipbuilder who ``won the war for us,'' in Gen. Dwight Eisenhower's view, by his prodigious feats of engineering and production. The LCVP, or ``Higgins boat,'' is the shallow-draft front-ramp craft that landed many men and vehicles on D-Day.
Mulberries: Two massive artificial harbors built by the British and towed across the Channel to France. After a disastrous raid on Dieppe in August 1942, the Allies concluded that the French ports were too well defended to attack from the sea. But ports would be critical to landing the enormous quantities of equipment and supplies needed to sustain an invasion, so the Mulberries - one British, one American - were designed and built. Rows of intentionally sunken ships served as breakwaters.
Operation Fortitude: A series of elaborate deceptions designed to fool the Nazis into believing the Allies would land where they would not, and that the real invasion was a feint. Phantom armies (with real radio traffic and high-profile generals), rubber tanks, poorly camouflaged (on purpose) fake landing craft, even loudspeakers blaring sounds of tanks on maneuvers from dummy encampments were among the ruses. The ``turning'' of every German agent in Britain (the Double Cross System) was an important component of the successful deception, as was the breaking of the Nazis' Enigma code - a fact that wasn't revealed publicly until the early 1970s.
Operation Overlord: Code name for the Allied landings.
X-Craft: Four-man midget submarines that did reconnaissance on invasion beaches. They also guided the swimming tanks (DDs) ashore at Sword and Juno.