Another name for Sirius (3,4)
I believe the answer is:
dog star
'another name for sirius' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for dog star that I've seen before include "Sirius in the sky" , "clearly visible shiner" , "'Another name for the Sirius constellation (3,4)'" , "Canine constellation" , "slightly flashy night-spot?" .)