Legendary ship (4)
I believe the answer is:
argo
'legendary ship' is the definition.
(ship in Greek myth)
This is the entire clue.
(Other definitions for argo that I've seen before include "Jason's craft" , "Stars once recognised in the south" , "Ship involved in the quest for the Golden Fleece" , "Name of ship sailed by Jason in search of the Golden Fleece" , "Mythical ship" .)