The Collaborative International Dictionary of English v.0.48:

Volt ampere \Volt amp[`e]re\ (Elec.)
   A unit of electric measurement equal to the product of a volt
   and an ampere. For direct current it is a measure of power
   and is the same as a watt; for alternating current it is a
   measure of apparent power.
   [Webster 1913 Suppl.]