"Short wheelbase" refers to the length of the distance between the front and rear wheels of a vehicle. It means that the distance is relatively small, which can make the vehicle more maneuverable and able to turn in tight spaces. Full definition
In some markets (depending on the manufacturer), short wheelbase models are excluded completely, and only long wheelbase variants are sold. (en.wikipedia.org)
The chassis by itself is 150 pounds lighter and has a 5.2 inch shorter wheelbase too. (autoweek.com)
Well, with that big V6 sat pretty high in the chassis and a relatively short wheelbase, the transition from grip to slip was sudden and unpredictable. (evo.co.uk)