Variations are usually a parameter of a game action or event that adds random to some other parameter of the action/event. An example good of this are the parameters speed and speedVariation of the shoot_particles game action where speedVariation will modify the final value of the speed parameter.
There are two kind of variations that will be explained below.
Positive variation will add to the main value another value that ranges from 0 to the value of the variation variable. For example, in shoot_particles the parameter amount is positivelly variated by amountVariation, if amount were 5 and amount variation were 6 the final result could range from 5 to 11.
If the speed of the object is 1, speed_var 0.4 will create speeds which are between 1 and 1.4