Origins
The word 'cordial' carries the human heart at its centre. It descends from Latin 'cor,' genitive 'cordis,' meaning 'heart,' through Medieval Latin 'cordiālis' and Old French 'cordial.' The Proto-Indo-European root is *ḱḗr, which produced parallel words for 'heart' across the Indo-European family: Greek 'kardía,' Old Irish 'cride,' Lithuanian 'širdis,' and Old English 'heorte' (which became modern English 'heart').
When 'cordial' first appeared in English in the late fourteenth century — Chaucer uses 'cordial' in 'The Canterbury Tales' — it carried a medical sense. Medieval physicians classified certain medicines and foods as 'cordials' because they were believed to invigorate the heart, which was regarded as the seat of vitality. A cordial might be a warm spiced drink, a medicinal elixir, or a restorative tonic. This pharmaceutical meaning survives in British English, where 'cordial' still refers to a sweet concentrated fruit drink diluted with water, and in the term 'cordial' for certain liqueurs.
The figurative sense — warm, sincere, heartfelt — developed alongside the medical one. By the fifteenth century, 'cordial' was being used to describe people, greetings, and relationships characterised by genuine warmth. A 'cordial welcome' is one that comes from the heart, not merely from politeness. This emotional sense eventually became the dominant meaning in most contexts.
Proto-Indo-European Roots
The Latin root 'cor' is remarkably productive in English. 'Courage' came through Old French 'corage,' originally meaning 'heart' or 'innermost feelings,' from Vulgar Latin *corāticum. 'Accord' combines 'ad-' (to) with 'cor' — literally 'heart to heart,' meaning agreement. 'Discord' is the opposite: hearts apart. 'Record' originally meant to learn by heart, from 're-' (again) and 'cor.' 'Concord' is hearts together. Even 'core,' though its precise etymology is debated, may derive from the same Latin root.
The Greek cognate 'kardía' gave English its medical vocabulary for the heart: 'cardiac,' 'cardiology,' 'electrocardiogram,' 'tachycardia,' 'pericardium.' Thus English has two parallel streams of heart-words — the Latin stream (cordial, courage, accord) and the Greek stream (cardiac, cardiology) — both flowing from the same Proto-Indo-European source.
One of the most famous uses of 'cordial' in diplomatic history is the 'Entente Cordiale' of 1904, the series of agreements between the United Kingdom and France that resolved colonial disputes and laid the groundwork for their alliance in the First World War. The phrase means 'cordial understanding' — an agreement reached not through legal compulsion but through mutual goodwill. It had been used earlier, in the 1840s, to describe a previous period of Anglo-French amity.
Later History
In C. S. Lewis's 'The Chronicles of Narnia,' Lucy receives a 'cordial' from Father Christmas — a magical healing potion carried in a diamond bottle. Lewis was drawing on the old medicinal sense: a liquid that restores vitality, a medicine for the heart. The word choice is precise and etymologically apt, a quiet signal from an author who was also a distinguished scholar of medieval and Renaissance literature.
The journey of 'cordial' from a Latin anatomical term through medieval pharmacology to modern social vocabulary illustrates how the metaphorical life of the heart — as the seat of feeling, sincerity, and warmth — shapes language across centuries. When we describe someone as 'cordial,' we are, whether we know it or not, locating their friendliness in their heart.