Middle of day, run out to get mum bouquet (5)
I believe the answer is:
aroma
'bouquet' is the definition.
(bouquet can mean a wine's aroma)
'middle of day run out to get mum' is the wordplay.
'middle of' indicates the central letters.
'run out' becomes 'RO' (cricket abbreviation).
'to get' means one lot of letters go next to another.
'mum' becomes 'ma' (ma can mean mother).
The middle letter of 'day' is 'a'.
'a'+'ro'+'ma'='AROMA'
(Other definitions for aroma that I've seen before include "Pervasive atmosphere" , "Strong smell" , "Spicy fragrance" , "Perfume" , "Bouquet" .)