Wordnet 3.0
NOUN (1)
1. 
 coil forming the part of an electrical circuit such that changing current in it induces a current in a neighboring circuit; 
- Example: "current through the primary coil induces current in the secondary coil"[syn: primary coil, primary winding, primary]
WordNet (r) 3.0 (2006):
primary coil
    n 1: coil forming the part of an electrical circuit such that
         changing current in it induces a current in a neighboring
         circuit; "current through the primary coil induces current
         in the secondary coil" [syn: primary coil, primary
         winding, primary]