Crossword Genius

Fellow leaves one city for another (7)

Ross

I believe the answer is:

chester

I'm a little stuck... Click here to teach me more about this clue!

'fellow' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for chester that I've seen before include "Walled city on the river Dee" , "See 8" , "County town south of Liverpool" , "County town of northwest England" , "Walled English city" .)

I've seen this clue in The Telegraph and The Mirror.
Want a hint initially instead of a full solution? Install my app