Rod and ball forming traffic barrier (7)
I believe the answer is:
bollard
'traffic barrier' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe there's an association between them I don't understand?
'rod and ball forming' is the wordplay.
'and' means one lot of letters go next to another.
'forming' indicates anagramming the letters.
'rod' put after 'ball' is 'ballrod'.
'ballrod' anagrammed gives 'BOLLARD'.
Can you help me to learn more?
(Other definitions for bollard that I've seen before include "Roadside post" , "Thick post for mooring" , "Post on road or quay" , "Mooring post - traffic restriction device" , "Short post barring traffic" .)