The Collaborative International Dictionary
Equidiurnal
Equidiurnal \E`qui*di*ur"nal\, a. [Equi- + diurnal.]
Pertaining to the time of equal day and night; -- applied to
the equinoctial line.
--Whewell.
Wiktionary
equidiurnal
a. Pertaining to the time of equal day and night; applied to the equinoctial line.