Compensation for travelling group (6)
I believe the answer is:
offset
'compensation' is the definition.
(offset is a kind of compensation)
'travelling group' is the wordplay.
'travelling' becomes 'off' (to go off is to go travelling).
'group' becomes 'set' (set is a kind of group).
'off'+'set'='OFFSET'
'for' is the link.
(Other definitions for offset that I've seen before include "Balance out" , "Something that compensates" , "Amount by which something is out of line" , "Type of printing of efts" , "Place at an angle to the main alignment" .)