Transit

n. [Lat. transitus, from transire, to go over; It. & Sp. transito, Fr. transit. See TRANSIENT.] 1. The act of passing; passage through or over. In France you are now . . . in the transit from one form of government to another. Burke.

2. The act or process of causing to pass; conveyance; as, the transit of goods through a country.
3. A line of passage or conveyance through a country; as, the Nicaragua transit. E. G. Squier.
4. (Astron.) (a.) The passage of a heavenly body over the meridian of a place, or through the field of a telescope. (b.) The passage of a smaller body across the disk of a larger, as of Mercury or Venus across the sun’s disk, or of a satellite or its shadow across that of its primary. (c.) A transit-instrument, or transit-compass.

Lower transit (Astron.), the passage of a heavenly body across that part of the meridian which is below the horizon.—Surveyor’s transit, a transit-compass.—Upper transit (Astron.), the passage of a heavenly body across that part of the meridian which is above the horizon.