English and Spanish both trace to PIE *men- — to think — yet diverged: Germanic through memory, Latin through abstraction. Esperanto simply chose the Latin form deliberately, making ancestry a design decision rather than an accident. Against all of this, Chinese 心 (xīn) starts with the organ seen in sacrifice, and never separated feeling from reason in a single word. Where the Indo-European family asks what the mind does, 心 asks where it lives.
Old English gemynd (with collective prefix ge-) meant primarily memory and intention before broadening to the full cognitive faculty by Middle English. The semantic drift from 'memory' to 'cognition' happened gradually across the 12th–15th centuries.
Reached Spanish through the Latin accusative mentem via Vulgar Latin. A learned register word; everyday Spanish often substitutes cabeza (head) or cerebro (brain). The adverbial suffix -mente (rápidamente, claramente) descends from the same Latin mens — 'with a rapid mind' compressed into a grammatical ending.
Oracle bone script (c. 1200 BCE) shows a shape unmistakably resembling the heart: a curved body with trailing vessels. As a radical it appears in hundreds of characters for thought, emotion, intention, and moral character — 思 (sī, to think), 忘 (wàng, to forget), 忍 (rěn, to endure), 怀 (huái, to cherish). The organ and the psyche were never assigned separate words.
心 alone covers the literary and classical sense of mind-as-heart. Modern Chinese extends the concept through compounds: 心智 (xīnzhì, cognitive mind), 心理 (xīnlǐ, psychology, lit. heart-principle), 思维 (sīwéi, cognition). All radiate from this one pictogram.
Zamenhof derived menso directly from Latin mens in 1887. It sits alongside spirito (spirit) and cerbo (brain, from Latin cerebrum); menso is the preferred philosophical term for the cognitive mind. The -o ending is the only morphological addition beyond the borrowed root.
The question every language answers differently is not 'what is the mind' but 'where did we first think to look for it.'