the.com/unicorn

means A mythical horse-like creature with a single spiraling horn on its forehead, and by extension any rare, magical, or unattainable thing — including a privately held startup valued at over a billion dollars.

from From Latin 'unicornis' — 'unus' (one) plus 'cornu' (horn) — a tidy translation of Greek 'monokeros,' both describing the single-horned beast that ancient writers swore lived in distant India. The creature wandered into the Bible too, where Hebrew 're'em' (probably a wild ox) got rendered as 'unicorn' by early translators, lending the myth a holy gloss. The startup sense is far younger: a venture capitalist coined it in 2013 to capture how rare such billion-dollar companies were thought to be — as rare, the joke went, as the animal itself.