thumb|right|300px|The gentle and pensive maiden has the power to tame the unicorn, fresco, probably by Domenico Zampieri, c. 1602 (Palazzo Farnese, Rome) A unicorn (from Latin unus 'one' and cornu 'horn') is a mythological creature. Though the modern popular image of the unicorn is sometimes that of a horse differing only in the horn on its forehead, the traditional unicorn also has a billy-goat beard, a lion's tail, and cloven hooves—these distinguish it from a horse. Marianna Mayer has observed (The Unicorn and the Lake), "The unicorn is the only fabulous beast that does not seem to have been conceived out of human fears. In even the earliest references he is fierce yet good, selfless yet solitary, but always mysteriously beautiful. He could be captured only by unfair means, and his single horn was said to neutralize poison."The Legend of the Unicorn, Geocities.com

Unicorns in antiquity

A one-horned animal (which may be just a bull in profile) is found on some seals from the Indus Valley Civilization. Seals with such a design are thought to be a mark of high social rank.

right|thumb|The aurochs An animal called the Re'em ( ) is mentioned in several places in the Hebrew Bible, often as a metaphor representing strength. "The allusions to the re'em as a wild, un-tamable animal of great strength and agility, with mighty horn or horns ( , , , , , comp. ), best fit the aurochs (Bos primigenius). This view is supported by the Assyrian rimu, which is often used as a metaphor of strength, and is depicted as a powerful, fierce, wild mountain bull with large horns." This animal was often depicted in ancient Mesopotamian art in profile, with only one horn visible.

The translators of the Authorized King James Version of the Bible (1611) employed unicorn to translate re'em, providing a recognizable animal that was proverbial for its un-tamable nature.

• "God brought them out of Egypt; he hath as it were the strength of the unicorn."--
• "God brought him forth out of Egypt; he hath as it were the strength of an unicorn."--
• "His glory is like the firstling of his bullock, and his horns are like the horns of unicorns: with them he shall push the people together to the ends of the earth."--
• "Will the unicorn be willing to serve thee, or abide by thy crib? Canst thou bind the unicorn with his band in the furrow? or will he harrow the valleys after thee? Wilt thou trust him, because his strength is great? or wilt thou leave thy labour to him? Wilt thou believe him, that he will bring home thy seed, and gather it into thy barn?"--
• "Save me from the lion's mouth; for thou hast heard me from the horns of unicorns."--
• "He maketh them (the cedars of Lebanon) also to skip like a calf; Lebanon and Sirion like a young unicorn."--
• "But my horn shalt thou exalt like the horn of the unicorn: I shall be anointed with fresh oil."--
• "And the unicorns shall come down with them, and the bullocks with their bulls; and their land shall be soaked with blood, and their dust made fat with fatness."--