Mean about single flower (7)
I believe the answer is:
anemone
'flower' is the definition.
(I know that anemone is a type of flower)
'mean about single' is the wordplay.
'about' is an anagram indicator.
'single' becomes 'one' (a single thing - only one).
'mean' is an anagram of 'anem'.
'anem'+'one'='ANEMONE'
(Other definitions for anemone that I've seen before include "Sea plant or garden flower" , "Pretty flower or sea animal" , "Woodland plant, eg the windflower" , "Bright flower or sea plant" , "Buttercup-like flower or sea animal" .)