Etymology
Advertisement
Dies Irae 
literally "day of wrath," first words of Latin hymn of Last Judgment, attributed to Thomas of Celano (c. 1250). See diurnal + ire.
Related entries & more 
Advertisement
head over heels (adv.)
1726, "a curious perversion" [Weekley] of Middle English heels over head (late 14c.) "somersault fashion," hence "recklessly." Head (n.) and heels long have been paired in alliterative phrases in English, and the whole image also was in classical Latin (per caput pedesque ire).
Related entries & more