"gigue" is pronounced as "zheeg" in French. The "g" is pronounced like the "s" in "measure", and the "u" is silent.

A gigue is most typically (probably almost always, with a few exceptions) in a compound meter, such as 6/8 or 3/6, etc.

IMSLP.org

A gigue is a lively dance of the Baroque era, usually written in compound time (e.g. 3/8, 6/8) and frequently emphasising the third beat of the bar, rather than the first.

Galliard, gavotte and gigue are dances. They begin with G.