how many people don’t know what religion is? how many people atheist? i know, its non of my business. okay, let say i’m not so religious man, but deep down in my heart, i believe that those religion guide us to the peaceful and happy life, here on earth or in heaven.
Lets get serious now, Religion has been defined in a wide variety of ways. Most definitions attempt to find a balance somewhere between overly sharp definition and meaningless generalities. Some sources have tried to use formalistic, doctrinal definitions while others have emphasized experiential, emotive, intuitive, valuational and ethical factors.
I found in wikipedia.org that a religion is a set of beliefs and practices generally held by a human community, involving adherence to codified beliefs and rituals and study of ancestral or cultural traditions and mythology, as well as personal faith and mystic experience. The term “religion” refers to both the personal practices related to communal faith and to group rituals and communication stemming from shared conviction.
Religion is often described as a communal system for the coherence of belief focusing on a system of thought, unseen being, person, or object, that is considered to be supernatural, sacred, divine, or of the highest truth. Moral codes, practices, values, institutions, traditions, and rituals are often traditionally associated with the core belief, and these may have some overlap with concepts in secular philosophy. Religion is also often described as a “way of life”.
The development of religion has taken many forms in various cultures. “Organized religion” generally refers to an organization of people supporting the exercise of some religion with a prescribed set of beliefs, often taking the form of a legal entity. Other religions believe in personal revelation and responsibility. “Religion” is sometimes used interchangeably with “faith” or “belief system,”[1] but is more socially defined than that of personal convictions.
Now, how many religion exist in this world? there is no exact number for this answer, but according to the adherent.com there are over 4,200 religions based on their statistics. there is so many difficulties to trace down this kind of information. however, we could easily know some of them with large number of adherent.

based on the picture above:
1. CHRISTIANITY : 2.1 billion
2. ISLAM : 1.3 billion
3. NON-ADHERENT (SECULAR/ATHEIST) : 1.1 billion
4. HINDUISM : 900 million
5. CHINESE FOLK RELIGION : 394 million
6. BUDDHISM : 376 million
7. PRIMAL INDIGENOUS (”PAGAN”) : 300 million
8. AFRICAN TRADITIONAL & DIASPORIC : 100 million
9. SIKHISM : 23 million
10. JUCHE : 19 million
11. SPIRITISM : 15 million
12. JUDAISM : 14 million
13. BAHÁ’Í FAITH : 7 million
14. JEHOVAH’S WITNESSES : 6 million
15. JAINISM : 4 million
16. SHINTO : 4 million
17. CAO DAI : 4 million
18. ZOROASTRIANISM : 2 million
19. TENRIKYO : 2 million
20. NEO-PAGANISM : 1 million
21. UNITARIAN UNIVERSALISM : 800,000
22. RASTAFARI MOVEMENT : 600,000
yes, there so many thing that we just need to discuss, ok then. lets do, but some other time of course. Hope this give you clue.
regards,
YanZ