The term anthem means either a specific form of Anglican church music (in music theory and religious contexts), or more generally, a song (or composition) of celebration, usually acting as a symbol for a distinct group of people, as in the term "national anthem" or "sports anthem".

The word is derived from the Greek ἀντίφωνα (antiphōna) via Old English antefn, a word which originally had the same meaning as antiphon.

An anthem is a form of church music, particularly in the service of the Church of England, in which it is appointed by the rubrics to follow the third collect at both morning and evening prayer. Several anthems are included in the British coronation service. The words are selected from Holy Scripture or in some cases from the Liturgy, and the music is generally more elaborate and varied than that of psalm or hymn tunes. Though the anthem of the Church of England is analogous to the motet of the Roman Catholic and Lutheran Churches, both being written for a trained choir and not for the congregation, it is as a musical form essentially English in its origin and development.

Everything (or every thing), is all that exists; the opposite of nothing, or its complement. The totality of things relevant to some subject matter. Without expressed or implied limits, it may refer to anything. The Universe is often defined as everything that exists. It may refer to an anthropocentric worldview, or the sum of human experience, history, and the human condition in general.

In theoretical physics, a theory of everything (TOE) is a theory that would explain and unify all known fundamental interactions of nature in a single model. Originally, the term was used playfully in regard to overgeneralized theories. However, it became a popular way of referring to the “holy grail” of physics. A theory of everything in philosophy would ask: "Why is reality understandable?" "Why are the laws of nature as they are?" "Why is there anything at all?"