therm·i·on 
(thûrmī′ən)
(thûrmī′ən)n.
An electrically charged particle, especially an electron, emitted by a conducting material at high temperatures.
therm′i·onic (-mī-ŏnĭk) adj.
- megaphonic
- megapixel
- megaplex
- megapode
- megapolis
- Megara
- megaron
- megascopic
- megascopically
- megasporangium
- megaspore
- megasporic
- megasporocyte
- megasporogenesis
- megasporophyll
- megastructure
- megatherium
- megaton
- megatonnage
- megavitamin
- megavolt
- megavoltage
- Megawati Soekarnoputri
- Megawati Sukarnoputri
- megawatt