The Collaborative International Dictionary of English v.0.48:

Electrostatic \E*lec`tro*stat"ic\, a.
   Pertaining to electrostatics.
   [1913 Webster]

WordNet (r) 3.0 (2006):

electrostatic
    adj 1: concerned with or producing or caused by static
           electricity; "an electrostatic generator produces high-
           voltage static electricity" [syn: electrostatic,
           static]