The use of the word religion to mean theism is a Johnny come lately, Mrrz, and its fundamental meaning requires no icons or theism.

" It is commonly regarded as consisting of a personÕs relation to God or to gods or spirits.[2] Many religions have narratives, symbols, traditions and sacred histories associated with their deity or deities, that are intended to give meaning to life. They tend to derive morality, ethics, religious laws or a preferred lifestyle from their ideas about the cosmos and human nature.
The word religion is sometimes used interchangeably with faith or belief system, but it is more than private belief and has a public aspect. Most religions have organised behaviors, congregations for prayer, priestly hierarchies, holy places and scriptures.
Academics studying the subject have defined religion into three broad categories: world religions, a term which refers to transcultural, international faiths, indigenous religions, which refers to smaller, culture-specific religious groups, and new religious movements, which refers to recently developed faiths.[3]"


1.
a. Belief in and reverence for a supernatural power or powers regarded as creator and governor of the universe.
b. A personal or institutionalized system grounded in such belief and worship.
2. The life or condition of a person in a religious order.
3. A set of beliefs, values, and practices based on the teachings of a spiritual leader.
4. A cause, principle, or activity pursued with zeal or conscientious devotion.

An excerpt on the various definitions from WordIQ:

Defining "religion"
Beyond the above, very broad definition of religion, there are a variety of uses and meanings for the word "religion." Some of the approaches are as follows:
One definition, sometimes called the "function-based approach," defines religion as any set of beliefs and practices that have the function of addressing the fundamental questions of human identity, ethics, death and the existence of the Divine (if any). This broad definition encompasses all systems of belief, including those that deny the existence of any god, those that affirm the existence of one God, those that affirm the existence of many gods, and those that pass on the question for lack of proof.
A second definition, sometimes called the "form-based approach," defines religion as any set of beliefs which makes claims that lie beyond the realm of scientific observation, according to some authority or personal experience with the Divine. This narrower definition places "religion" in contradistinction with rationalism, secular humanism, atheism, and agnosticism, which do not appeal to authority or personal experience in coming to their beliefs, but instead appeal to their interpretation of science.
A third definition, sometimes called the "physical evidence approach," defines religion as the beliefs about cause and effect that Occam's Razor would remove as recognizing causes that are more than what is both true and sufficient to explain the physical evidence. By this definition then, non-religion is any set of beliefs that admits no more causes of natural things than such as are both true and sufficient to explain their appearance.
A fourth definition, sometimes called the "organizational approach," defines religion as the formal institutions, creeds, organizations, practices, and rules of conduct, of all major, institutionalized religions. This definition places "religion" in contradistinction to "spirituality," and therefore does not include the claims "spirituality" makes to actual contact, service, or worship of the Divine. In this definition, however, religion and spirituality are not mutually exclusive: a religious person may be spiritual or unspiritual, and a spiritual person may be religious or non-religious. By analogy, "religion" is the coal, wood, or gasoline, while "spirituality" is the fire.


A