magneto
magneto (mag*nē"to) , noun
A small electric generator with an armature rotating in a magnetic field, having a secondary winding that generates a high voltage, such as one used to generate a voltage sufficient to cause a spark to jump between the poles of a spark plug in an internal-combustion engine.
Magneto- , prefix
[See Magnet.]
A prefix meaning pertaining to, produced by, or in some way connected with, magnetism.