What is the definition of the word “Non-Muslim”.

I have heard that some Muslim people call and use the word “Non-Muslim” to other religion people but I differ it. Because I have a question that what does Non-Muslim mean? Is it the appropriate word “Non-Muslim” to use any body and Allah uses this word in any verse in Al-Quran? If any body knows any verse of Al-Quran where is used “Non-Muslim”, please inform me about this verse.

I know that Allah defines in Al-Quran five types of human beings; these are Mumeen, Muttaqeen, Munafeeq, Mushriq and Kafeer. But I don’t know that why do we use the word “Non-Muslim”, if we say that any body is born in Muslim family then they will be a Muslim and born in any other religion (Hindu, Christian, Jewish etc) then they will be Non-Muslim; then I can’t accept it (as per Al-Quran, if there is not use the word “Non-Muslim”). Muslim means the most obedient to Allah and I must believe that we know all the definition of the word “obedient”. So if any body is not obedient to Allah then we must call or tell him Kafeer. Because when Allah told to all angels for bow down to Adam then Iblis did not do it; [2:34] when we said to the angels, "Fall prostrate before Adam," they fell prostrate, except Iblis; he refused, was too arrogant, and became Kaffeer”. All Hindus are Mushriq but few is Kafeer into those Hindus, same as other religion; even that if we see in those people whose are born in Muslim family then can see that most of people are Mushriq, Munafeeq and Kafeer and few people are Mumeen and Muttaqeen. So Mushriq, Munafeeq and Kafeer have no identification of religion and they are not Muslim or Non-Muslim, they are different type of Human beings. But Allah says in Al-Quran several times that Allah forgives those Mushriq and Munafeeq whose repent for their fault and sinful life to Him then become a Muslim but Kafeer never become Muslim. So I think that Non-Muslim is not correct word to use any body on the religion sense.