Short answers, pulled from the story.
Baroque music spans from about 1600 to 1750. Scholars divide it into three approximate phases: early Baroque (1580-1650), middle Baroque (1630-1700), and late Baroque (1680-1750), though exact dates remain debated.
The word baroque derives from the Portuguese barroco, meaning an irregularly shaped pearl. It was first applied to music in an anonymous satirical review of Rameau's Hippolyte et Aricie, printed in the Mercure de France in May 1734, where it was used as a criticism of the music's dissonance and complexity.
Jacopo Peri is credited with writing the first operas, including Dafne and L'Euridice. These works grew out of the Florentine Camerata, a gathering of humanists and musicians who met under the patronage of Count Giovanni de' Bardi.
Basso continuo is a continuous accompaniment in which bass instruments such as the cello or viol play a bassline while keyboard players or lutenists improvise chords above it. Figured bass notation, using numbers and symbols above the bassline, guided players in choosing which intervals to play.
Alessandro Stradella originated the concerto grosso style in his Sonate di viole. Arcangelo Corelli then developed the form extensively, alternating sections between the full orchestra and a smaller group, and Antonio Vivaldi was among his students who later built on those principles.
The four core dances are the allemande, the courante, the sarabande, and the gigue. The allemande is in moderate tempo with German Renaissance origins; the courante is in triple meter; the sarabande is a slow Spanish dance with an emphasis on the second beat; and the gigue is a lively piece in compound meter with roots in the British Isles.