/juːˈnænɪməs/
[adjective] When everyone in a group agrees on something completely, with no one disagreeing. For example, a unanimous vote means every single person voted the same way.
Unanimous hides two Latin words inside it — 'one' and 'soul' — meaning a group so agreed they share a single spirit.
To be unanimous is, at its deepest root, to share a soul. The word comes from the Latin adjective 'unanimus', which was built from two smaller words: 'unus', meaning 'one', and 'animus', meaning 'mind', 'spirit', or 'soul'. For the Romans, when a group reached complete agreement, they were not merely thinking the same thought — they were, in a poetic sense, breathing with one breath, animated by a single inner force.
The word 'unus' is ancient, tracing back to the Proto-Indo-European root '*oi-no-', which meant 'one' or 'single'. This same root traveled across languages and centuries to give us the Latin 'uni-' prefix, which then passed into Old French as 'uni-' and eventually into English words like 'unity', 'union', and 'universe'. Every time you use the prefix 'uni-', you are reaching back to that prehistoric root for oneness.
The second half, 'animus', has a similarly rich history. It comes from the Proto-Indo-European root '*ane-', meaning 'to breathe' or 'to blow'. From this root, Latin developed both 'animus' (the rational mind or spirit) and 'anima' (the breath or soul of a living creature). These Latin forms passed through Old French and into English in various shapes: 'animus' itself entered English directly in the 19th century to mean a feeling of hostility, while 'animate', 'animal', and 'animation' all descend from 'anima' through the Latin 'animare', meaning 'to give life to'.
The combined Latin adjective 'unanimus' — and its related noun 'unanimitas', meaning 'oneness of mind' — was used regularly by Roman writers. Cicero and Livy both employed forms of the word to describe political harmony or shared purpose among citizens or allies. When Latin gave rise to the later scholarly language used across medieval Europe, 'unanimitas' passed into Late Latin and then into Old French as 'unanime', before arriving in English in the early 17th century. The first clear uses in English appear around the 1610s, and the word arrived fully formed, already carrying its modern meaning.
What is perhaps most striking about 'unanimous' is how philosophical its origin is. Modern usage tends to treat it as a dry, procedural word — a unanimous decision, a unanimous verdict — but its Latin bones describe something almost mystical: a gathering of separate people who have, for a moment, become one in spirit. The Romans understood agreement not just as matching opinions but as a kind of shared inner life. In that sense, every time a jury returns a unanimous verdict or a committee reaches unanimous consensus, they are — without knowing it — briefly claiming to share a single soul.