The word(part) or abbreviation/acronym/initialism So, SO or .so has several meanings, depending on context:

• The common English conjunction/adverb/etc. (see our entry "so" in our sister dictionary project, Wiktionary).
• Significant other, any romantic interest.
• Somalia, ISO 3166-1 alpha-2 country code
• Somali language (ISO 639)
• the top-level domain for Somalia (as in http://www.gov.so)
• Canton of Solothurn, a canton in Switzerland.
• StarOffice, a package of office software
• in algebra, a special orthogonal group or the corresponding Lie algebra.
• So is the title of an album by Peter Gabriel
• The shared object file format and the respective filename extension .so (as in /usr/lib/libfoo.so).