Real Dictionary

magneto in American English
an electric generator in which one or more permanent magnets produce the magnetic field; esp., a small machine of this sort connected with and run by an internal-combustion engine, used to generate the electric current providing a spark for the ignition
noun: a small electric generator with an armature that rotates in a magnetic field provided by permanent magnets, as a generator supplying ignition current for certain types of internal combustion engines or a hand-operated generator for telephone signaling

magneto in British English
noun: a small electric generator in which the magnetic field is produced by a permanent magnet, esp one for providing the spark in an internal-combustion engine

magneto- in American English
magnetism, magnetic force
combining form: a combining form representing magnetic or magnetism in compound words

magneto- in British English
combining form: indicating magnetism or magnetic properties