Three rings interwoven with very large moulding (5)
I believe the answer is:
ovolo
'very large moulding' is the definition.
'ovolo' can be an answer for 'moulding' (I've seen this before). I'm not certain of the 'very large' bit.
'three rings interwoven' is the wordplay.
'three rings' means three substitutions for 'ring'.
'ring' becomes 'O' (O is the shape of a ring).
'ring' becomes 'O' (O is the shape of a ring).
'ring' is an insertion indicator.
'interwoven' becomes 'vol' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'o'+'o'='oo'
'oo' going around 'vol' is 'OVOLO'.
'with' is the link.
Can you help me to learn more?
(Other definitions for ovolo that I've seen before include "Convex moulding" , "Rounded architectural moulding" , "decorative strip" , "Thumb" .)