The word comes from the combination of two Greek words, 'not place'. The modern meaning of the word Utopia comes from Thomas More's book, Utopia, referring to a perfect organized society based on what were highly liberal, egalitarian concepts for the time it was written, 1516. The meaning blurs considerably in usage. An idea which is considered 'Utopian' is either being referred to as impractical, or extolled as a virtue of the concept. The idea of creation of a perfect society is rarely taken seriously, but Utopia is the usual description of such a society.
Examples of Utopia:
Full text of Utopia by Sir Thomas More