a ring worn tightly in front of another ring to prevent the latter from slipping off the finger.
The Hidden Histories Of “Humpty Dumpty,” “London Bridge,” And “Ring Around The Rosie”These hidden stories behind these three popular nursery rhymes may not be well known but they certainly make songs like "Humpty Dumpty" a little more interesting.
Origin of guard ring
First recorded in 1810–20
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for guard ring
Also called: guard, keeper ring jewellery an extra ring worn to prevent another from slipping off the finger
an electrode used to counteract distortion of the electric fields at the edges of other electrodes in a capacitor or electron lens
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