{ A*cron"yc (&?;), A*cron"ych*al (&?;), } a. [Gr. 'akro`nychos at nightfall; 'a`kros + ny`x night.] (Astron.) Rising at sunset and setting at sunrise, as a star; -- opposed to cosmical.

&fist; The word is sometimes incorrectly written acronical, achronychal, acronichal, and acronical.