Religion: A system of worship which recognizes one or more supreme beings. Examples: Christianity, Buddhism, Hinduism. Any religion may contain elements of other categories.
Philosophy: A system of thought that literally is "a search for wisdom." Often the philosophies follow the teachings of an individual, such as the ancient philosophies of Plato and Aristotle or the more modern philosophies of Karl Marx and other communist leaders.
Worldview: A way of looking at the world in which experience and behavior are determined by the assumptions and beliefs a person or culture may have at its center. These may be determined by culture rather than a formal religion, although both will usually be involved. Examples:
Guilt and innocence, typically the West
Shame and honor, typically Asia and the Middle East
Unclean and clean, typically the Middle East
Fear and power (animism), typically tribal, although elements pervade all of the world's religions
Many other classifications of exist, depending upon the purpose of the definitions. The above are typically used to describe spiritual foundations.