This is the 6996th most frequent Portuguese word.
islam
Islam: A monotheistic religion founded on the teachings of the Prophet Muhammad, centered around submission to Allah.
Here, 'islam' refers to the religion itself as a proper noun in the context of a general statement about world religions.
O islam é uma das religiões monoteístas mais praticadas no mundo.
Islam is one of the most practiced monotheistic religions in the world.
In this case, 'islam' is used in the academic context referring to the study of the religion as a subject matter.
Estudei muito sobre o islam durante o curso de ciência da religião.
I studied a lot about Islam during the religious studies course.
Here, 'islam' is employed to signify the set of religious principles and practices associated with the religion.