SIC is a multi-package multi-language interpretor. A package is a collection of tools logically grouped together to provide some related applications, e.g. a plotting ensemble like GreG. A package can reference several languages: for example, GreG contains 4 languages: GREG1, GREG2, GREG3 for 1-D, 2-D and 3-D data plotting, and GTV for the basic plot actions. SIC itself has 5 languages: SIC, VECTOR, ADJUST, GUI and TASK, with the last two in ``Library only'' mode.