Well, I would agree with the meteorological definition, that's the one I was taught in my physics class as well. Wikipedia [says][1]:

> In physics, velocity is the rate of change of displacement (position). It is a vector physical quantity; both magnitude and direction are required to define it. The scalar absolute value (magnitude) of velocity is speed [...]. For example, "5 meters per second" is a scalar and not a vector, whereas "5 meters per second east" is a vector.


  [1]: http://en.wikipedia.org/wiki/Velocity