Passeio vs. calçada
Both passeio and calçada refer to the area usually adjacent to a road where pedestrians walk. The primary difference lies in regional usage between European Portuguese (Portugal) and Brazilian Portuguese. While they are often interchangeable in dictionaries, native speakers choose one over the other based on their country.
Passeio
A1In Portugal, passeio is the standard and most common word for the raised paved path for pedestrians along the side of a street. In Brazil, while passeio technically means sidewalk in urban planning contexts (often called passeio público), in daily conversation, the word is almost exclusively used to mean a tour, trip, or leisure walk.
Os peões devem sempre circular pelo passeio.
(Pedestrians must always circulate on the pavement.)
É proibido estacionar o carro em cima do passeio.
(It is forbidden to park the car on the sidewalk.)
A câmara municipal vai alargar o passeio desta rua.
(The city council is going to widen the pavement on this street.)
Ele tropeçou no passeio enquanto corria para o autocarro.
(He tripped on the curbside while running for the bus.)
As crianças desenharam no passeio com giz.
(The children drew on the sidewalk with chalk.)
Calçada
A2In Brazil, calçada is the universal everyday word for sidewalk or pavement. In Portugal, calçada usually refers specifically to the road surface material (cobblestones), such as the famous calçada portuguesa (Portuguese pavement), rather than the walkway itself, though it may be understood in context.
O vizinho está limpando a calçada com uma vassoura.
(The neighbor is cleaning the sidewalk with a broom.)
Cuidado com o buraco na calçada.
(Watch out for the hole in the pavement.)
As mesas do restaurante ocupam toda a calçada.
(The restaurant tables occupy the entire sidewalk.)
A prefeitura exige que a calçada esteja em boas condições.
(The city hall requires the sidewalk to be in good condition.)
Eu encontrei o João andando na calçada em frente à loja.
(I met João walking on the sidewalk in front of the store.)
Summary
To sound like a local: use passeio when you are in Portugal and calçada when you are in Brazil. If you use passeio in Brazil, people might think you are going on a trip. If you use calçada in Portugal, people might think you are discussing the cobblestones themselves rather than the walkway.