Bright star seen in April, so extraordinary (7)
I believe the answer is:
polaris
'bright star' is the definition.
(I've seen this in another clue)
'april so extraordinary' is the wordplay.
'extraordinary' is an anagram indicator.
'april'+'so'='aprilso'
'aprilso' anagrammed gives 'POLARIS'.
'seen in' acts as a link.
(Other definitions for polaris that I've seen before include "star (non-movie)" , "Star useful for navigation" , "Star near the N pole of the heavens" , "North Star - missile" , "one belonging in the heavens" .)