(noun) visionary theorizing / (noun) a systematic body of concepts especially about human life or culture / (noun) a manner or the content of thinking characteristic of an individual, group, or culture / (noun) the integrated assertions, theories and aims that constitute a sociopolitical program
The largely concealed structure of values which informs and underlies our factual statements is part of what is meant by 'ideology'. By 'ideology' I mean, roughly, the ways in which what we say and believe connects with the power-structure and power-relations of the society we live in.
I like this definition a lot