'Zenithal' definitions:

Definition of 'zenithal'

From: WordNet
adjective
Relating to or located at or near the zenith

Definition of 'Zenithal'

From: GCIDE
  • Zenithal \Ze"nith*al\, a. Of or pertaining to the zenith. "The deep zenithal blue." --Tyndall. [1913 Webster]