First there are the Utopias. Utopias are sites with no real place. They are sites that have a general relation of direct or inverted analogy with the real space of Society.... There are also, probably in every culture, in every civilization, real places--places that do exist and that are formed in the very founding of society--which are something like counter-sites, a kind of effectively enacted utopia in which the real sites, all the other real sites that can be found within the culture, are simultaneously represented, contested, and inverted. Places of this kind are outside of all places, even though it may be possible to indicate their location in reality. Because these places are absolutely different from all the sites that they reflect and speak about, I shall call them, by way of contrast to utopias, heterotopias.
From: "Of Other Spaces: Utopias and Heterotopias" from Foucault's Architecture /Mouvement/ Continuité (1967). Translated by Jay Miskowiec.
Basic Definition from the New Dictionary of the history of Ideas
Dystopia is utopia's polarized mirror image. While utilizing many of the same concepts as utopia—for example, social stability created by authoritarian regimentation—dystopia reads these ideas pessimistically. Dystopia angrily challenges utopia's fundamental assumption of human perfectibility, arguing that humanity's inherent flaws negate the possibility of constructing perfect societies, except for those that are perfectly hellish. Dystopias are solely fictional, presenting grim, oppressive societies—with the moralistic goal of preventing the horrors they illustrate.
From: Sisk, David W., "Dystopia." New Dictionary of the History of Ideas. Ed. Maryanne Cline Horowitz. Vol. 2. Detroit: Charles Scribner's Sons, 2005. p606-610. From Gale Virtual Reference Library.
Andrew Wood's Omnitopia
Omnitopia enacts a structural and perceptual enclave whose apparently distinct locales convey inhabitants to a singular place.
When you can flow from place to place, experiencing it all as one vast interior, cocooned in your own bubble, interacting with other people and natural parts of the world only as a series of objects, you're in omnitopia.
From: Andrew Wood's website
Andrew Wood's Book, City Ubiquitous: Place Communication and the Rise of Utopia
While some well-regarded scholars argue that utopianism is a Western phenomenon and that utopias do not appear outside the West until the influence of More's Utopia was felt, others have argued that utopianism developed independently in non-Western cultures. Thomas More invented a literary genre, but there are texts in the West and outside it that predate More's Utopia that describe a nonexistent society that is identifiably better than the existing society. Probably the best-known early non-Western utopia is "The Peach Blossom Spring," a poem of T'ao Yüan Ming (also known as T'ao Ch'ien) (365–427), that describes a peaceful peasant society, but there are golden ages, earthly paradises, and other forms of utopianism found in Sumerian clay tablets and within Buddhism, Confucianism, Hinduism, Islam, and Daoism.
From "Utopia - Non-western Utopianism" by Lyman Tower Sargent in The Science Encyclopedia from JRank.