Just another –sphere, like Pierre Teilhard de Chardin’s noosphere or Vladimir Vernadsky’s biosphere, the ideosphere of Douglas Hofstadter or Michael Crichton’s sci-fi piece.
This term in particular was conceived in the womb of Eastern European linguistic theory, genetically influenced by the likes of Mikhail Bakhtin, and born to Estonian thinker Juri Lotman. Lotman raised it on harsh words, calling it (in his book The Semiosphere) “the semiotic space necessary for the existence and functioning of languages, not the sum total of different languages.” By this he meant only that the semiosphere should not simply be a term under which to collect the proliferation of signs, but rather the precondition of expression itself, the vast field of extant meanings that give communication a chance without holding it to its word. The semiosphere is not where language in all its manifestations exists, but where it lives.
Hotly contested today as a possible link toward the new interdisciplinary field of biosemiotics, the term has outgrown its father's aspirations for a career in literary analysis. Of course when we say ‘hotly contested’ we mean that an academic journal or two has published a well-shrouded invective against one or the other field and its advances onto cordoned off turf. And when we say ‘new’ we mean that Jakob von Uexküll’s works from 1900 on were mostly forgotten, and that C.S. Peirce’s theory of signs is not technically ‘old’ if his essential works have just been republished in two volumes.
The semiosphere seems rather like the primordial soup of culture, making us, in our recognition of identity, the effects of a significatory autopoiesis and the atoms of something wholly different.
see Kalevi Kull's "On semiosis, Umwelt, and semiosphere" at: http://www.zbi.ee/~kalevi/jesphohp.htm