In astronomy, a transit (or astronomical transit) is a phenomenon when a celestial body passes directly between a larger body and the observer. As viewed from a particular vantage point, the transiting body appears to move across the face of the larger body, covering a small portion of it.[1]
The word “transit” refers to cases where the nearer object appears smaller than the more distant object.
https://en.wikipedia.org/wiki/Transit_(astronomy)
From NASA:
A transit is when one object crosses in front of another in space. This can happen in a lot of different ways. One example is when the Moon passes between Earth and the Sun. The Moon is “transiting” the Sun. This is also called a solar eclipse.