transitn.[L. transitus, from transire to go over: cf. F. 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 or route of passage or conveyance; as, the Nicaragua transit.(E. G. Squier.)4. (Astron.) The passage of a heavenly body over the meridian of a place, or through the field of a telescope.()5. An instrument resembling a theodolite, used by surveyors and engineers; -- called also transit compass, and surveyor's transit.()()Lower transit (Astron.), the passage of a heavenly body across that part of the meridian which is below the polar axis. -- Surveyor's transit. See Transit, 5, above. -- Transit circle (Astron.), a transit instrument with a graduated circle attached, used for observing the time of transit and the declination at one observation. See Circle, n., 3. -- Transit compass. See Transit, 5, above. -- Transit duty, a duty paid on goods that pass through a country. -- Transit instrument. (Astron.) (a) A telescope mounted at right angles to a horizontal axis, on which it revolves with its line of collimation in the plane of the meridian, -- used in connection with a clock for observing the time of transit of a heavenly body over the meridian of a place. (b) (Surv.) A surveyor's transit. See Transit, 5, above. -- Transit trade (Com.), the business conected with the passage of goods through a country to their destination. -- Upper transit (Astron.), the passage of a heavenly body across that part of the meridian which is above the polar axis.()v. t. (Astron.) To pass over the disk of (a heavenly body).()