Authors in a story sometimes use literary devices to describe something instead of saying it directly.  Many times this makes the story much more descriptive and interesting. Some examples of these are metaphor, simile, imagery, vignette , alliteration, oxymoron, foreshadowing and so on and so forth. The book I have been reading is The Ultimate Hitchhikers Guide to the Galaxy by Douglass Adams. Douglass uses a lot of literary devices when he is writing. Some of them are pretty silly. Here are some examples.
"How do you know" said Zaphod in a voice that would make a vegan snow lizard feel chilly. This is a metaphor. Here is another example.
Those-very view-who witnessed the event and survived swear that the whole hundred thousand square miles of desert rose into the air like a mile-thick pancake and flipped itself over. This is a simile. Douglass Adams uses metaphors almost to the extent that they don't make sense but this makes his books much more descriptive and fun to read.