n.
- the state of being notched at the edge or the process of notching at the edge, as some leaves or the page of a book, particularly a reference work with thumb indexing.
[The Running Sky — Tim Dee]
Lexicon
adjective
relating to heaven or the sky: the empyrean domain where human will and God’s will became as one.
noun (the empyrean)
heaven, in particular the highest part of heaven: the unapproachable splendor of the empyrean.
• literary: the visible heavens; the sky: we rose through the polluted air into the clear empyrean above.
[A Room with a View — E. M. Forster]