n. in astronomy, the passage or transit of a star across the meridian at the point opposite to the point of culmination. In the case of a circumpolar star it is often called lower culmination or transit sub polo.On a surveyors’ transit, to turn (the telescope) over so as to make it point, in the opposite direction.n. The act of passing; a passing over or through; a passage; the act of moving, or the state of being conveyed; also, the act or process of causing to pass; conveyance: as, the transit of goods through a country; the problem of rapid transit in cities.n. A line of passage or conveyance through a country: as, the Nicaragua transit.n. In astronomy: The passage of a heavenly body aeross the meridian of any place. The right ascension of such a body is the sidereal time of its upper transit.n. The passage of a celestial body (specifically either of the planets Mercury and Venus) across the sun's disk, or of a satellite, or the shadow of a satellite, across the face of its primary. The passage of the moon across the sun's face, however, is called an eclipse.n. An abbreviation of transit-circle or transitinstrument.n. An instrument used in surveying for measuring horizontal angles.To pass over the disk of, as of a heavenly body.