equinoctial
adjective /ˌiːkwɪˈnɒkʃl/,  /ˌekwɪˈnɒkʃl/
  /ˌiːkwɪˈnɑːkʃl/,  /ˌekwɪˈnɑːkʃl/
- connected with an equinoxWord Originlate Middle English (in the sense ‘relating to equal periods of day and night’): via Old French from Latin aequinoctialis, from aequinoctium, from aequi- ‘equal’ + nox, noct- ‘night’.