What is the origin of 'sleep tight'?
Read moreOne of the mysteries of the English language finally explained.
Definition of acronical in US English:
acronical
(also achronical)
adjective
AstronomyOf the rising or setting of a celestial object: occurring at or just after sunset.
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.
