Origins
The word 'cold' descends from Old English 'ceald' or 'cald' (cold), from Proto-Germanic *kaldaz (cold), from PIE *gel- (cold, to freeze).βββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββ It is one of the most fundamental environmental terms in the Germanic languages, with cognates in every branch: German 'kalt,' Dutch 'koud,' Swedish 'kall,' Danish 'kold,' Norwegian 'kald,' Icelandic 'kaldur,' and Gothic 'kalds.' The uniformity of the cognates across all Germanic branches testifies to the word's antiquity and stability.
The PIE root *gel- produced a large family across the Indo-European languages. In Latin, it gave 'gelΕ«' (frost, ice, cold) and 'gelΔre' (to freeze, to congeal). From these Latin forms, English acquired a cluster of learned borrowings: 'gelatin' (a substance produced by boiling collagen β named for its congealing properties), 'jelly' (from Old French 'gelΓ©e,' from Latin 'gelΔta,' a frozen/congealed thing), 'congeal' (from Latin 'con-gelΔre,' to freeze together), and 'gelid' (extremely cold). The word 'glacier' came through French from Vulgar Latin *glaciΔrium, from Latin 'glaciΔs' (ice), also from the same PIE root. So 'cold,' 'gelatin,' 'jelly,' 'congeal,' 'gelid,' and 'glacier' all descend from the same ancestral word for freezing.
The metaphorical uses of 'cold' in English are systematically opposed to those of 'warm,' reflecting the pervasive conceptual metaphor that maps temperature onto emotion. 'Cold' means emotionally distant ('a cold person'), unfeeling ('cold-hearted'), deliberately cruel ('cold-blooded,' 'in cold blood'), or unwelcoming ('a cold reception'). 'Cold comfort' is comfort so slight it offers no warmth. 'Cold war' is a conflict waged without the heat of direct combat. 'Cold shoulder' (deliberate social snubbing) may derive from the practice of serving a cold shoulder of mutton to an unwelcome guest β a chilly meal instead of a hot one.
Later History
The use of 'cold' to mean a respiratory illness ('to catch a cold,' 'a head cold') dates from the sixteenth century and reflects the once-universal belief that exposure to cold weather caused the illness. While modern medicine has established that colds are caused by viruses (primarily rhinoviruses) rather than cold temperatures, the linguistic association persists in English and many other languages β German 'ErkΓ€ltung' (a cold, literally 'a getting-cold') encodes the same folk theory.
The phonological history of 'cold' in English shows the characteristic Middle English shortening of vowels before consonant clusters: Old English 'ceald' had a diphthong that was simplified to a short vowel in many dialects, producing 'cald' and eventually 'cold.' The spelling with '-ol-' reflects the standard London/East Midlands pronunciation that became the basis of modern Standard English, while Scots English preserves 'cauld' (reflecting a different dialectal development of the Old English diphthong), as in Robert Burns's 'Auld Lang Syne' where the related word 'auld' (old) shows the same vowel.