What is the meaning of Atheism?

A non-belief in deities.

Belief that no deities exist (sometimes including rejection of other religious beliefs).

A lack of belief in deities, or a belief that there is insufficient evidence to believe in a god.

Absence of belief that any deities exist (including absence of the concept of deities).

Absence of belief in a particular deity, pantheon, or religious doctrine (notwithstanding belief in other deities).

(Can we verify this sense?) A rejection of all religions, even non-theistic ones.

Source: wiktionary.org