Titanomachia literally means "battle of the gods". This was a turning point in Greek mythology. So the story goes something like this:
Uranus and
Gaea (
heaven and
earth) have 12 kids. Of particular interest is one
Cronus, their youngest son. He was given the
responsibility of
castrating his
father by his
mother, in order to separate
heaven from
earth. After this, he becomes
King of the
Titans. He and his
sister Rhea give birth to several children (
Hestia,
Demeter,
Hera,
Hades, and
Poseidon) all of which
Cronus swallows, because he was told by his
parents that one of his own
children would overthrow him.
Rhea hides
Zeus from
Cronus, and makes
Cronus believe he has eaten
Zeus (by wrapping a stone in cloths). When
Zeus grew old enough, he confronted his
father and forced him to
regurgitate his
brothers and
sisters, then waged
war on
Cronus and the other
titans. After 10 years of
fighting this
war (the Titanomachia ;), Zeus and his
siblings imprisoned the
titans in a cave beneath
Tartarus.
Final note: this information was taken from a few (potentially not the best available sources) basically, other E2 nodes, and the Encyclopedia Britannica