Wikipedia
Sung-through (also through-sung) is a term describing a musical, musical film, or opera with no spoken dialogue, except perhaps for some occasional lines spoken in the course of a song but remaining part of the song's lyrics rather than constituting stand-alone dialogue. Conversations, speeches, and musings are communicated musically though a combination of recitative, aria, and arioso. Early versions of this include the Italian genre of opera buffa, a light-hearted form of opera that gained prominence in the 1750s. Most recently, Lin-Manuel Miranda, in Hamilton, has introduced the idea of communicating "dialogue" through rap, therefore keeping the spirit of a sung-through musical, without actually singing everything. A through-sung opera may also be described as through-composed.