Brown boy's pears (8)
I believe the answer is:
williams
'brown' is the definition.
Both the answer and definition are singular nouns.
Maybe you can see an association between them that I don't see?
'boy's pears' is the wordplay.
'boy' becomes 'William' (boy's name).
'pears' becomes 's' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'william'+'s'='WILLIAMS'
Can you help me to learn more?
(Other definitions for williams that I've seen before include "Type of dessert pear" , "Serena --, tennis player" , "... after which [STATE = TENNESSEE] writer" , "Tennessee --, dramatist" , "Tennessee, Wm. Carlos ---, authors" .)