a coil of wire around an iron core; becomes a magnet when current passes through the coil
"The mechanic replaced the faulty solenoid in the starter motor because it failed to generate enough magnetic force to turn over the engine."
A coil of wire that acts as a magnet when an electric current flows through it.
"The mechanic replaced the faulty solenoid because the starter motor wouldn't engage without electricity flowing through its internal coil to create a magnetic pull."
The word comes from the French term solénoïde, which was borrowed from Ancient Greek. It originally meant "pipe-shaped," combining words for a channel or pipe with a suffix meaning "resembling."