To the definitions already published I add some more: 1º_ 'So' is an archaism for "su" (possessive adjective). 2º_ It is an adjective little used to enhance a following noun that in some cases becomes the prefix so- and is almost always derogatory. 3º_ As an acronym in Spanish we can find it in "operating system" (for computer equipment), "Second officer", "Observation service", "without opinion", . . . 4º_ In English, but seen in Spanish, it is an abbreviation of Sold Out ("everything available sold"). 5º_ SO is the chemical formula of sulfur monoxide. 6º_ ' . so' is the internet domain for Somalia.
