What is Ideologies?

Ideologies definition and meaning on Dictionary terms:
noun, plural iA.deA.olA.oA.gies.
the body of doctrine, myth, belief, etc., that guides an individual, social movement, institution, class, or large group.
such a body of doctrine, myth, etc., with reference to some political and social plan, as that of fascism, along with the devices for putting it into operation.
Philosophy. the study of the nature and origin of ideas. a system that derives ideas exclusively from sensation.

theorizing of a visionary or impractical nature.