sine die

c. 1300, sauns, saun, "without" (mid-12c. in surnames), from Old French san, sans, sen, senz (some of the forms with adverbial genitive -s) "without, except, apart, not counting." This is cognate with Provençal senes, Old Catalan senes, Old Spanish sen (Spanish sin), Old Italian sen, all from Vulgar Latin *sene, from Latin sine "without," an enlarged form of sed, se "without" (from PIE root *sen(e)- "apart, separated;" see sunder).

"A French word which has existed long in English without becoming naturalized; now archaic or affected, except as used in heraldry ..." [Century Dictionary, 1891]; OED writes that the words limited modern use is "chiefly with reminiscence of Shakespere," which it spells that way. In reference to fonts, by 1927, short for sans-serif. Sans souci, French, as an adverbial phrase "free from care, without care or concern," was the name of Frederick the Great's royal palace at Potsdam. 

Proto-Indo-European root meaning "to shine," in derivatives "sky, heaven, god."

It forms all or part of: adieu; adios; adjourn; Asmodeus; circadian; deific; deify; deism; deity; deodand; deus ex machina; deva; dial; diary; Diana; Dianthus; diet (n.2) "assembly;" Dioscuri; Dis; dismal; diurnal; diva; Dives; divine; joss; journal; journalist; journey; Jove; jovial; Julia; Julius; July; Jupiter; meridian; Midi; per diem; psychedelic; quotidian; sojourn; Tuesday; Zeus.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit deva "god" (literally "shining one"); diva "by day;" Avestan dava- "spirit, demon;" Greek delos "clear;" Latin dies "day," deus "god;" Welsh diw, Breton deiz "day;" Armenian tiw "day;" Lithuanian dievas "god," diena "day;" Old Church Slavonic dini, Polish dzień, Russian den "day;" Old Norse tivar "gods;" Old English Tig, genitive Tiwes, name of a god.