Heavenly bodies in type of blood bank (4)
I believe the answer is:
orbs
'heavenly bodies' is the definition.
(orb can mean a celestial body)
'type of blood bank' is the wordplay.
'type of blood' becomes 'O' (O is a blood group).
'bank' becomes 'RBS' (Royal Bank of Scotland).
'o'+'rbs'='ORBS'
'in' is the link.
(Other definitions for orbs that I've seen before include "Poetic eyes, bros" , "Ball shapes" , "Spherical objects" , "circles" , "Eyeballs" .)