Meaning

noun a diode vacuum tube in which the flow of electrons from a central cathode to a cylindrical anode is controlled by crossed magnetic and electric fields; used mainly in microwave oscillators

originEtymology tree Old French magnetebor. Pre-Greekbor.? Ancient Greek Μάγνης (Mágnēs) Ancient Greek μᾰ́γνης (mắgnēs)bor. Latin magnēsbor. Middle English magnete English magnet Proto-Indo-European *-tḗr Proto-Indo-European *-trom Proto-Hellenic *-tron Ancient Greek -τρον (-tron)bor. English -tron English magnetron From magnet + -tron.

Etymology from Wiktionary, CC BY-SA 3.0