Main Page | See live article | Alphabetical index Si or si or SI may stand for: Si, the lunar deity in Mohican mythology si, one of Spanish language words pronounced sē, like "see": sí (accented) for "yes" and si (unaccented) for "if" Si, the seventh note of solfege SI, the Système International d'Unités, the (metric) International System of Units silicon (Si, symbol for the chemical element) Slovenia (ISO country code) Smithsonian Institution Socialist International Sports Illustrated Staten Island, a borough of New York City and an island in the Hudson River Swedish Institute (Svenska institutet) This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.