OPERA
"...a drama set to music and made up of vocal pieces with orchestral accompaniment and with orchestral overtures and interludes..."*

BAROQUE
The term Baroque probably ultimately derived from the Italian word barocco, which was a term used by philosophers during the Middle Ages to describe an obstacle in schematic logic. Subsequently the word came to denote any contorted idea or involuted process of thought. Another possible source is the Portuguese word barroco (Spanish barrueco), used to describe an irregular or imperfectly shaped pearl, and this usage still survives in the jeweller's term baroque pearl. In art criticism the word Baroque came to be used to describe anything irregular, bizarre, or otherwise departing from established rules and proportions.*

ENCYCLOPÆDIA BRITANNICA

 Detail from Nicola Porpora's Componimento drammatico Gli orti Esperidi