Major or Minor in astronomy? (4)
I believe the answer is:
ursa
'major or minor in astronomy?' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ursa that I've seen before include "and 18 Down: The Great Bear" , "Major and Minor, the Bear constellations" , "- Major, - Minor, prominent constellations" , "Latin for the Great Bear, . . . . Major" , "stars" .)