The Collaborative International Dictionary
Undersky
Undersky \Un"der*sky`\, n. The lower region of the sky.
Floating about the undersky.
--Tennyson.
Wiktionary
undersky
n. The lower region of the sky.
Usage examples of "undersky".
The theory is it will be much less disorienting to go back and forth between Settlertown and Hades if our undersky matches the real one precisely.