Lateral chord displacement, in plain English we would refer to as "wag."  This term should NOT be confused with draw force, what we call "tug."

 Lateral chord displacement is nothing more than the distance a gate will vary from its true path of travel to one side or the other under conditions which may apply a side-ward force. With this condition, we are almost always talking about the load or wind deflection. The variables which will affect the deflection amount of the gate frame have to do with the construction format such as, standard construction, dual track, box frame, modular, fully welded with proper trusses, and fillers, like slats, wood, chain link gauge and the presents of signs or other adornments.

In engineering terms, deflection is the degree to which a structural element is displaced under a load. It may refer to an angle or a distance.