This is the 7510th most frequent Spanish word.
islam
The monotheistic religion founded on the teachings of Prophet Muhammad.
Here, 'islam' is used as a proper noun referring to the religion, treated with capitalization to reflect its status as the name of a cultural system.
El islam es una de las religiones más prominentes del mundo.
Islam is one of the most prominent religions in the world.
In this sentence, 'islam' is used in a historical context, referring to the religion's development and history as an entity studied academically or culturally.
Aprendí mucho sobre la historia del islam durante mi viaje.
I learned a lot about the history of Islam during my trip.
'Islam' here emphasizes its role in defining the structure and practices pertaining to the religion, mentioning specific characteristics known to it.