Maisonette and Walk-up

Maisonette noun - A self-contained apartment (usually on two floors) in a larger house and with its own entrance from the outside.

Walk-up and maisonette are semantically related. In some cases you can use "Walk-up" instead a noun "Maisonette".

Walk-up noun - An apartment building without an elevator.

Maisonette and walk-up are semantically related. You can use "Maisonette" instead a noun phrase "Walk-up".