The house with its own Tube station (7)

I believe the answer is:

mansion

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

'the house' is the definition.
(a mansion is a large house)

I don't understand the remainder of the clue.

(Other definitions for mansion that I've seen before include "Large house" , "Large dwelling" , "housing" , "large residence" , "Manor house" .)

I've seen this clue in the Evening Standard.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.