Silver ring gone (3)
I believe the answer is:
ago
'gone' is the definition.
(I've seen this in other clues)
'silver ring' is the wordplay.
'silver' becomes 'ag' (Ag is the chemical symbol for silver).
'ring' becomes 'o'.
'ag'+'o'='AGO'
(Other definitions for ago that I've seen before include "Time past" , "Previously" , "(Years) before the present time" , "Earlier, gone by" , "In past times" .)