Etymology

From Sanskrit दिन ‎(dina) +‎ -ము ‎(-mu). Ultimately from Proto-Indo-European *dyew- ‎(“to shine”), whence also *déy-no-, whence Lithuanian diena, Old Church Slavonic дьнь ‎(dĭnĭ). Other cognates include Old Armenian տիւ ‎(tiw, “daytime”), Latin diēs ‎(“day”).