Measure of silver included in ready change (7)
I believe the answer is:
yardage
'measure' is the definition.
(thesaurus)
'silver included in ready change' is the wordplay.
'silver' becomes 'ag' ('Ag' can be a synonym of 'silver').
'included in' indicates putting letters inside.
'change' is an anagram indicator.
'ready' anagrammed gives 'yarde'.
'ag' put within 'yarde' is 'YARDAGE'.
'of' acts as a link.
(Other definitions for yardage that I've seen before include "Distance measured in imperial units" , "Distance covered" , "Golf or American Football statistic" , "Distance sometimes measured in paces" , "Distance (eg in golf)" .)