Transit of Phobos from Mars Reference Libraries
Mars' Moon Phobos -- in astronomy, innermost moon, or natural satellite, of Mars. Phobos orbits Mars at a distance of only 9,378 km (5,627 mi), closer to its planet than any other moon in the solar system. In fact, it is so close that the force of Mars's gravity is stronger than the force keeping the moon in its orbit, so the radius of Phobos's orbit is decreasing at the rate of about 1.8 m...
- The horn of a unicorn considered as a medical or pharmacological ingredient.
- A winged horse with a single horn on its head; a winged unicorn.