a semiconductor diode whose capacitance changes to match applied voltage, used to tune circuits by varying the reactance.
Origin of varactor
1955–60; var(iable re)actor
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Word Origin for varactor
C20: probably a blend of variable reactor
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