Did include a space for a crown (6)
I believe the answer is:
diadem
'for a crown' is the definition.
('diadem' can be a synonym of 'crown')
'did include a space' is the wordplay.
'include' indicates putting letters inside.
'space' becomes 'em' (in typography, a space as wide as a letter 'm').
'did' going around 'a' is 'diad'.
'diad'+'em'='DIADEM'
(Other definitions for diadem that I've seen before include "Small jewelled crown" , "Headband worn by sovereign" , "headwear" , "Royal crown" , "Tiara" .)