air-core

[ air-kawr, -kohr ]
/ ˈɛərˌkɔr, -ˌkoʊr /

adjective Electricity.

having a nonmagnetic core, as one of fiber or plastic, encircled by a coil (air-core coil), or containing one or more such coils: air-core transformer.

Origin of air-core

First recorded in 1890–95
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019