solenoid: Meaning and Definition of

so•le•noid

1. an electric conductor wound as a helix with small pitch, or as two or more coaxial helices, so that current through the conductor establishes a magnetic field within the conductor.
2. Also calleda switch controlled by such an arrangement, in which a metal rod moves when the current is turned on: used in automotive starting systems.
3. a space formed by the intersection of isobaric and isosteric surfaces.