A syllable applied, in solmization, to the note B; more recently, to the seventh tone of any major diatonic scale. It was added to Guido's scale by Le Maire about the end of the 17th century.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). si. Retrieved September 24, 2026, from http://smartdefine.org/si/definitions/2061788 |
| Chicago | Webster's. 2011. "si" http://smartdefine.org/si/definitions/2061788 (accessed September 24, 2026). |
| Harvard | Webster's 2011, si, Smart Define, viewed 24 September, 2026, <http://smartdefine.org/si/definitions/2061788>. |
| MLA | Webster's. "si" 28 May 2011. Web. 24 September 2026. <http://smartdefine.org/si/definitions/2061788> |