It forms all or part of: hypno-; hypnosis; hypnotic; hypnotism; insomnia; somni-; somnambulate; somniloquy; somnolence; somnolent; Somnus; sopor; soporific.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit svapnah, Avestan kvafna-, Greek hypnos, Latin somnus, Lithuanian sapnas, Old Church Slavonic sunu, Old Irish suan, Welsh hun "sleep;" Latin sopor "a deep sleep;" Old English swefn, Old Norse svefn "a dream."
It forms all or part of: accumulate; accumulation; cave; cavern; cavity; coeliac; church; codeine; coelacanth; coeliac; coelomate; concave; cumulate; cumulative; cumulus; enceinte; excavate; kirk; kymatology; Kyrie eleison.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit svayati "swells up, is strong;" Greek kyein "to swell," koilos "hollow, hollowed out, spacious, deep;" Latin cumulus "a heap, pile, mass, surplus;" Lithuanian šaunas "firm, solid, fit, capable;" Middle Irish cua "hollow;" Armenian soyl "cavity."
also *ker-, Proto-Indo-European root meaning "to turn, bend."
It forms all or part of: arrange; circa; circadian; circle; circuit; circum-; circumcision; circumflex; circumnavigate; circumscribe; circumspect; circumstance; circus; cirque; corona; crepe; crest; crinoline; crisp; crown; curb; curvature; curve; derange; flounce (n.) "deep ruffle on the skirt of a dress;" krone; ring (n.1) "circular band;" ranch; range; ranger; rank (n.) "row, line series;" research; recherche; ridge; rink; rucksack; search; shrink.
It is the hypothetical source of/evidence for its existence is provided by: Latin curvus "bent, curved," crispus "curly;" Old Church Slavonic kragu "circle;" perhaps Greek kirkos "ring," koronos "curved;" Old English hring "ring, small circlet."