Apartamento vs. departamento vs. piso
The Spanish language features several words to describe living spaces, with 'apartamento', 'departamento', and 'piso' all referring in some way to what English speakers would call an 'apartment' or 'flat'. The usage of these terms can vary depending on the region.
Apartamento
An 'apartamento' is a type of housing unit that typically forms part of a larger building. It is equivalent to the English word 'apartment'.
Alquilé un apartamento en el centro de la ciudad.
(I rented an apartment in the city center.)
Este apartamento tiene tres dormitorios y dos baños.
(This apartment has three bedrooms and two bathrooms.)
Departamento
'Departamento' is used to refer to an apartment in some Latin American countries like Mexico and Argentina.
Mi departamento queda en el quinto piso del edificio.
(My department is on the fifth floor of the building.)
El alquiler del departamento incluye los servicios básicos.
(The rent for the department includes basic services.)
Piso
'Piso' is commonly used to refer to an 'apartment' or 'flat' in Spain. But it also means 'floor' in both Spain and Latin America.
Vivo en un piso con vistas al parque.
(I live in a flat overlooking the park.)
El piso está ubicado en un edificio moderno.
(The flat is located in a modern building.)
Summary
'Apartamento', 'departamento', and 'piso' are all Spanish words that can be used to refer to an apartment or flat. The term used can vary depending on the geographical location. For example, while you might rent a 'departamento' in Mexico, you'd find yourself looking for a 'piso' in Spain or an 'apartamento'in most other Spanish-speaking contexts.