The letters SIC may mean one of the following things:
SIC is the officially obsolete Standard Industrial Classification system used in the USA. Started in the 1930s, its last and final revision was in 1987. SIC codes are still prevalent in many private and public sector economic and business databases; nevertheless they have been officially replaced by the more service-sector oriented NAICS system.
[sic] or (sic) (Latin for 'thus') indicates that an unusual spelling or phrase is intended to be read or printed exactly as shown (rather than being an error) and should not be corrected. See List of Latin phrases.