/ˈhjuːmər/
[noun] The quality of being funny or amusing, or the ability to find things funny. In older medicine, it also referred to one of four body fluids that were believed to control a person's health and personality.
Your mood, your personality, and your sense of humour all trace back to the ancient belief that four bodily fluids controlled everything you felt.
The story of 'humour' begins in ancient medicine, with a theory that would shape how humans understood themselves for nearly two thousand years. The Greek physician Hippocrates, and later Galen, taught that the human body contained four vital fluids — blood, phlegm, yellow bile, and black bile — and that a person's health, temperament, and even personality depended entirely on the balance of these fluids. The Greeks called these fluids 'khumoi' (singular: 'khumos'), meaning 'juice' or 'sap', connecting the human body to the living world of plants and animals. This word carried the idea that the body, like the earth, ran on flowing liquids.
The Romans translated this idea almost directly. The Latin word 'humor' simply meant 'moisture', 'liquid', or 'fluid', and it slipped naturally into medical texts as the term for these four life-controlling substances. From classical Latin, the word passed into Old French as 'humour', keeping its medical meaning intact. It was this Old French form that arrived in English during the 14th century, carried along by the enormous cultural influence of French on the English language after the Norman Conquest of 1066.
In medieval and Renaissance England, the four humours were not just medical facts — they were a complete theory of personality. Too much blood made you 'sanguine': cheerful, energetic, and sociable. Too much phlegm made you 'phlegmatic': calm, slow, and unemotional. Too much yellow bile made you 'choleric': quick-tempered and aggressive. Too much black bile made you 'melancholic': sad, anxious, and withdrawn. These four temperament types, all born from the humour theory, are still used as personality descriptions today, long after anyone believed in the fluids themselves.
The leap from 'body fluid' to 'funny' is surprising, but it follows a perfectly logical path. By the 16th century, 'humour' in English had begun to mean a person's general mood or state of mind — the idea being that your mood was literally determined by your bodily fluids. From there, it was a short step to using 'humour' to mean a whim, a fancy, or a particular quirk of character. When we say someone is 'in a good humour' or ask someone to 'humour us' (meaning to go along with our wishes), we are using this transitional sense directly.
The specifically comic meaning — humour as the quality of being funny — developed during the 17th and 18th centuries. Writers and philosophers began to discuss 'humour' as a kind of playful, human quality: the ability to notice life's absurdities and find them amusing rather than distressing. By the time the great essayists of the 18th century were writing, 'humour' had come to describe a gentle, sympathetic form of comedy, distinct from sharp wit or biting satire. The word had travelled an extraordinary distance: from the liquid inside your body to the laughter inside your soul.
The root Latin word 'humor' also gave English several closely related words through different paths. Latin 'humor' → Old French 'humide' → English 'humid', meaning damp. Latin 'humor' also fed into 'humility' — though that word actually comes from a different Latin root, 'humus' meaning 'earth' or 'ground'. The shared sense of something low, wet, and earthy ties many of these words together in the imagination. Today, 'humour' sits comfortably in English as one of those rare words whose full history makes it feel richer and stranger every time you say it.