Something that is fatidic is prophetic or fateful. In mythology or literature, a fatidic encounter or dream foretells or foreshadows things that will happen.
The word fatidic comes from the Latin roots fatum, meaning "fate," and dicere, meaning "to speak or tell." Its literal meaning is "speaking fate." If a friend says something to you that turns out to be eerily accurate with regard to what happens down the road, you might look back and call that remark fatidic. The word is tied to mythology. In ancient Roman myths, the three sisters who spun the "thread" of human life were called the Fata (The Fates). A fatidic message in the stories often warned of future events.