Atheism is a non-belief in God. In your KS3 Religious Education lessons, you will be learning about the various different religions people believe. But what about those who have no religious beliefs?
If you take a look at a list of the most populous religions in the world, you might find a category for non-believers, or atheists. One such list has a category for "secular/agnostic/atheist", which, with 1.1 billion members, falls in third place behind Islam (1.2 billion) and Christianity (2.1 billion). This inclusion is intended to point out that a sizeable number of people have no religious beliefs.
What do these terms mean? An atheist is someone who does not believe in any supernatural beings or explanations for phenomena.
An agnostic is a person who does not claim absolute disbelief, but feels instead that the existence or non-existence of supernatural beings is unknowable and thus keeps an open mind on the topic. But what is meant by "secular"? The word itself refers to the world, and specifically to laws that derive from civil sources, rather than from religious scripture or law. A secular country is one in which religious power is limited to its own spheres, in governing its own organisation, rather than applying to all citizens. A secular country or organisation will not discriminate between followers of different religions, or no religion. Secularism is therefore not incompatible with religious belief, instead being a guarantee of religious freedom for all. The rare exception to this is where secular states have enforced atheism.