Hyperion begins "The Hegemony Consul sat on the balcony of his ebony spaceship and played Rachmaninoff's Prelude in C-sharp Minor on an ancient but well-maintained Steinway while great, green, saurian things surged and bellowed in the swamps below" (Prologue.1).
Um, what? Starting Hyperion is about as intimidating as putting yourself into cryonic fugue for a seven-year journey across the WorldWeb. (That's Hyperion-speak for freezing yourself like Walt Disney's head and hitching a ride on a spaceship across the galaxy.)
The dictionary feature on your e-reader can help you start your journey, but it's not going to get you to the planet Hyperion. Not only does Simmons use big words, he uses made-up words and phrases, like farcaster portal, fatline squirt, and time debt. Simmons doesn't explain these terms either, because that would be like a character in present day picking up something called the "telephone" and then defining it for you. It would pull you out of the story. Stick with it (and with us), and it'll all click into place. In no time, you'll feel like you're living 700 years in the future.