Definition of acronical in English:

acronical

Pronunciation /əˈkrɒnɪkl/

adjective

(also achronical)
Astronomy
  • Of the rising or setting of a celestial object: occurring at or just after sunset. Also in extended use. Compare "cosmical", "heliacal".

Origin

Late 16th century; earliest use found in John Blagrave (d. 1611), mathematician. From post-classical Latin acronychos or its etymon ancient Greek ἀκρόνυχος acronic + -al.