A minute part in range (5)
I believe the answer is:
ambit
'range' is the definition.
(I know that range can be written as ambit)
'a minute part' is the wordplay.
'minute' becomes 'm' (abbreviation).
'part' becomes 'bit' (both mean a piece of something).
'a'+'m'+'bit'='AMBIT'
'in' is the link.
(Other definitions for ambit that I've seen before include "Compass, scope" , "Range, scope" , "Scope or confines" , "Limits" , "Circumference" .)