Final answer:
Bel canto is the style of singing that involves agility and purity of tone, characterized by its emphasis on legato singing and vocal ornamentation.
Step-by-step explanation:
The style of singing that features agility and purity of tone is known as bel canto. This terminology literally means 'beautiful singing' in Italian and is associated with a vocal style that emerged during the late 18th century. The key characteristics of bel canto include smooth phrasing, a focus on legato singing, and the use of ornamental techniques such as trills and runs to showcase a singer's vocal agility.
Bel canto is not to be confused with opera, which is a form of theater where music, including singing, is a principal part of the performance. Chant refers to the rhythmic speaking or singing of words or sounds, often on a single pitch and used in religious rituals. Scat is a vocal improvisation with wordless vocables and nonsense syllables or without words at all, commonly used in jazz.