Being a fantasy writer, I use this word a lot, either within the story itself or in my outlines/character descriptions.
Pronounced as ih-THEER-ee-ul\ it means:
1. of or relating to the heavens : heavenly
2. being light and airy : delicate
The ethereal creature woke from the riverbank, stretched her gossamer wings, and flitted over the glistening water.
Enjoy your Saturday.