Catholicism originated as a European religion (and it remains centered in Italy, where the Vatican is located) however over the centuries it has spread widely across the world, and has more adherents outside of Europe than it has in Europe.
Catholicism.
predominantly Roman Catholicism
Christianity is the main religion, predominantly the Catholic denomination. Santeria is one of the main religions in Cuba. Catholicism is practiced mostly by the elite. Santeria is practiced by the majority of the population. It is an Afro-Cuban religion.
Roman Catholicism (80% or more of the population has such beliefs)
The European settlers brought both Catholicism and Protestantism from their native countries and went on from there
Catholicism is the oldest religion in Europe. It is also the largest.
Prior to the fall of the Romanovs and the rise of Communism, Russians were predominantly Russian Orthodox Catholics (as compared to Greek Orthodox or Roman Catholicism).
Yes, Catholicism = Catholic religion.
Basically, the European invaders in South America imposed their religion on the native population. This religion was usually Catholicism. This affects not only Spanish-speaking countries, but also Brazil, which was colonized by Portugal.
... Catholicism is a religion itself. The only Catholic religion is Catholicism.
Roman Catholicism is the main religion of Rwanda
Catholicism is the largest denomination within Christianity. Christianity itself is the largest religion in the entire world, hence Catholicism is a major world religion.