Musical oration of the kind common in the narrative and dialog sections of the opera and the oratorio, sung at the rhythm of the regular speech with several words along the same line is understood as Recitative.
While an aria is a long song that is performed by a single instrument and normally appears in an opera. It is an Italian word which means "air" in the 18th century. An artist would sing a song that would convey his or her emotions The aria had more interest in music than the recitative.
