The word "unicorn" is a direct borrowing from the Old French unicorne, which itself originates from the Latin ūnicornis. This Latin term is a compound of ūnus, meaning "one", and cornū, meaning "horn", thus literally translating to "one-horned". The concept stems from ancient Greek natural histories, which described a wild, horse-like Indian beast with a single horn. The word's logic is perfectly transparent, combining the idea of singularity with the defining physical attribute to name a mythical creature that has been a symbol of rarity and purity across European and Near Eastern cultures for millennia.

Structure: uni (one) + corn (horn) - uni: From Latin ūnus (one). A prefix meaning "single" or "one". - corn: From Latin cornū (horn). A root denoting a horn or horn-like projection.