Arm, for example (4)
I believe the answer is:
limb
'arm for example' is the definition.
(I know that arm is a type of limb)
This is all the clue.
(Other definitions for limb that I've seen before include "Part of body or branch of tree" , "Eg wing" , "Jointed appendage" , "Branch - arm - leg" , "A supporter" .)