Weeds are found in the back-street (5)
I believe the answer is:
tares
'weeds' is the definition.
The answer and definition can be both man-made objects as well as being plural nouns.
Perhaps they are linked in a way I don't understand?
'are found in the back-street' is the wordplay.
'found in' indicates putting letters inside.
'the back' says the letters should be written backwards.
'street' becomes 'st' (abbreviation).
'st' reversed gives 'ts'.
'are' put within 'ts' is 'TARES'.
Can you help me to learn more?
(Other definitions for tares that I've seen before include "Stare at the vetches" , "The weights of packaging" .)