Dog in orbit (5)
I believe the answer is:
pluto
This might be a double definition.
'dog' is the first definition.
(I have seen 'animated dog' mean 'pluto' so perhaps 'dog' could also mean 'pluto')
'orbit' is the second definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for pluto that I've seen before include "Greek god of the underworld" , "Planet furthest from the sun" , "heavenly body" , "Planet beyond Neptune" , "wartime acronym" .)