1. The crossing of a small celestial body in front of a larger one.

Venus and Mercury are in transit across the disk of the sun when seen from the earth.

2. The passage across the observer's meridian of a celestial body, or the crossing of the face of one body; for example, the sun, by the path of another; for example, Mercury or Venus, from the observer's viewpoint.

Thus passes away the glory of this world.