Backtrack, repeatedly refusing to hold book on quiet bridge (3)
I believe the answer is:
ivy
'bridge' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for ivy that I've seen before include "Clinging evergreen" , "Parasitical plant, companion to holly" , "Evergreen climber" , "Girl" , "Hedera helix" .)