an arrangement of siphon tubes that enables water in a heating apparatus to circulate by means of convection.
Origin of thermosiphon
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
a system in which a coolant is circulated by convection caused by a difference in density between the hot and cold portions of the liquid
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