A crown regularly seen in this abroad (5)
I believe the answer is:
tiara
'a crown' is the definition.
(tiara is a type of crown)
'regularly seen in this abroad' is the wordplay.
'regularly seen in' means one should take alternating letters.
'this'+'abroad'='thisabroad'
The alternating letters of 'thisabroad' are 'TIARA'.
(Other definitions for tiara that I've seen before include "Ornamental crescent-shaped headdress or Pope's diadem" , "Jewelled hair-band" , "Ornamental head band" , "Small crown" , "Women's head ornament" .)