a combining form representing magnetic or magnetism in compound words: magnetochemistry.
Also especially before a vowel, magnet-.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for magneto-
indicating magnetism or magnetic propertiesmagnetosphere
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for magneto-
word-forming element meaning "magnetic, magnetism," from Greek magneto-, combining form of magnes (see magnet).
Online Etymology Dictionary, © 2010 Douglas Harper