Nerd danced around one bistro (5)
I believe the answer is:
diner
'bistro' is the definition.
(thesaurus)
'nerd danced around one' is the wordplay.
'danced' indicates an anagram (I've seen 'dancing' mean this).
'around' means one lot of letters goes inside another.
'one' becomes 'i' (Roman numeral).
'nerd' with letters rearranged gives 'dner'.
'dner' placed around 'i' is 'DINER'.
(Other definitions for diner that I've seen before include "Small American eatery" , "Small US restaurant" , "Restaurant customer" , "US eatery" , "Buffet car" .)