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 25, 2026, from http://smartdefine.org/si/definitions/2061788 |
| Chicago | Webster's. 2011. "si" http://smartdefine.org/si/definitions/2061788 (accessed September 25, 2026). |
| Harvard | Webster's 2011, si, Smart Define, viewed 25 September, 2026, <http://smartdefine.org/si/definitions/2061788>. |
| MLA | Webster's. "si" 28 May 2011. Web. 25 September 2026. <http://smartdefine.org/si/definitions/2061788> |