Properly, "recitativo arioso," this is, a
recitative of a lyrical and expressive quality,
not, as usual, narrative and speechlike. The arioso style, therefore,
is midway between that of a recitative and an aria.
Historically, the arioso came earlier than the speech-like recitative.
All the composers of the Florentine
opera (Peri, Caccini, Monteverdi)
employed the "recitativo arioso," the expressive
and quasimelodic recitative. Bach
often uses the arioso for the concluding section of a recitative in order
to give it a particular expression of assurance or confidence.