Apartment and Maisonnette

Apartment noun - A room or set of rooms in a private house or a block used as a separate dwelling place.

Maisonnette and apartment are semantically related. In some cases you can replace term "Maisonnette" with "Apartment", this nouns are similar.

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

Apartment and maisonnette are semantically related. You can use "Apartment" instead a noun "Maisonnette".