Ground bass is a simple repeating bassline that continue the whole way through a piece of music whilst the melody changes over the top, pachabels canon is a good example of ground bass in music,

Figured bass - Composers wrote the melody of their compositions and the basic bassline, they left out the bassline harmonies, so they wrote numbers underneath the bassline in the gaps, the person playing the bassline (usually on a harpsichord) would have to improvise the gaps of the bassline, using the numbers as a guideline telling them what Chords to use.
Continuo - The part that is played with by the harpsichord, icludes a bassline and a harmony.
Concerto grosso - There is a large group of instrumentalists, playing with a small group of instrumentalists contrasting with each other, sometimes they play at the same time, sometimes they imitate each other. Concerto gross means "Big concert" in italian.
A string quartet is a group of four instrumentalists , two violins, a viola and a cello. This is an example of a string quartet

Vivaldi, Purcell, bach - These were three composers from the Baroque period here is an example of each composers music;
Vivaldi Four seasons - Autumn

Purcell Chacony in G minor

Bach - Brandenburg Concerto #3