Transit
Also called: shadow transit, meridian transit.
When a small body crosses the face of a larger one — a moon over Jupiter, or Mercury over the Sun.
Jupiter's moons and their shadows regularly cross the planet's disk: the shadow is a sharp black dot, the moon itself is hard to spot against the clouds. Mercury and Venus occasionally transit the Sun (only ever observe the Sun with a proper solar filter).
Astronomers also say an object transits when it crosses the meridian — that's when it's highest.