a small electric coil used to heat a liquid, as a cup of water, in which it is immersed.
Origin of immersion heater
First recorded in 1910–15
Also called immersion coil.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for immersion heater
an electrical device, usually thermostatically controlled, for heating the liquid in which it is immersed, esp as a fixture in a domestic hot-water tank
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