Serenade, serenata—an evening song.
Sextet—a composition for six voices or instruments.
Sextuplet—a group of six notes to be performed in the time ordinarily given to four of the same value. The sextuplet differs from a pair of triplets in having but one accent.
Simile, similiter—the same; indicating that the same general effect is to be continued.
Solfeggio, solfège—a vocal exercise sung either on simple vowels or on arbitrary syllables containing these simple vowel sounds. Its purpose is to develop tone quality and flexibility. These terms are also often applied to classes in sight-singing which use the sol-fa syllables.
Sopra—above.
Soprano—the highest female voice. Range approximately b—c'''.
Sostenuto—sustained or connected; the opposite of staccato.
Sotto—under. E.g., sotto voce—under the voice, i.e., with subdued tone.
Solmization—sight-singing by syllable.