Seat breaks with danger to star (8)
I believe the answer is:
asterisk
'star' is the definition.
(I know this)
'seat breaks with danger' is the wordplay.
'breaks' indicates an anagram.
'with' means one lot of letters go next to another.
'danger' becomes 'risk' (risk is a kind of danger).
'seat' is an anagram of 'aste'.
'aste'+'risk'='ASTERISK'
'to' is the link.
(Other definitions for asterisk that I've seen before include "Sign" , "Star in print" , "Footnote marker" , "Star-shaped character used in printing" , "Printed star" .)