This is the 6164th most frequent Portuguese word.
circular
To move around or travel in a circuit.
Here, 'circular' is used as a verb meaning 'to move around or circulate'.
Eu vou circular pelo bairro para conhecer melhor a região.
I will circulate around the neighborhood to get to know the area better.
In this sentence, 'circular' is an adjective describing the type of bus (a bus that travels a circulating route).
O ônibus circular passará em frente ao parque.
The circular bus will pass in front of the park.
Here, 'circular' is used as an adjective meaning 'round' or 'circular' in shape.