Firstly, I'm not sure what "the Orthodox religion" is. There's the Eastern Orthodox church, which is a Christian religion. There's Jewish Orthodox, which is, I hope obviously, a type of Judaism. There are also many other churches with "orthodox" in their name, including the Lutheran Orthodox Church and a branch of Bahai.
Secondly, the differences between any of these and Islam are so multitudinous that it's not reasonable to expect anyone to list all of them in detail. If you really want to know, you could take a World Religions or Comparative Religion class in college, which ought to give you the beginnings of an idea.
Taking those considerations into account, possibly the best possible answer to the question is that one of them is Islamic, and the other one isn't.
There is no difference. Islam is a religion.
Christianity, Roman Catholic and Orthodox, and Islam
Islam is the religion. Muslims are the people to practice/follow the religion of Islam.
Islam is the name of the religion & Muslim is the follower of Islam.
Persia used to be a country Islam is a religion.
islam is the true and ultimate religion and humanism is the freedom
Islam is the true and ultimate religion and Humanism is the freedom
Islam is a religion, while Muslim is a person who follows the religion of Islam. Islam is the faith, while Muslim is the follower of that faith.
Islam is the religion Muslim is the person who follows Islam's teaching
Islam and Catholic/Orthodox Christianity.
Canadians have the religion Christianity while morroccan have a religion Islam
Islam is the religion Muslim is the person who follows Islam's teaching