meridian line

An arc or part of the meridian of a place, terminated each way by the horizon. meridian-mark, s . A mark placed at some miles' distance from an observatory, and due south of the position of the transit-instrument, to serve as a means of marking the direction of the true south point of the horizon. mě-rid 1-on-al, a. & s. [Fr., from Lat. meridi onalis.] A. As adjective : 1. Of or pertaining to the meridian; hence, south erly. *2. Having a southerly aspect; facing the south. B. As subst.: The south. "The meridional (which they of the Ocean call south, and those of the Mediterranean Sea Zezzo Giorno) commonly is rainy and boisterous."- Boyle : Works , ii. 611. meridional-arc, s. An arc of the earth, measured along the meridian, with the view of ascertaining the length of a degree in different latitudes, and thence calculating the exact form of the earth. [ARC, OBLATE.] meridional-distance, s . [MERIDIAN DISTANCE.] meridional-parts, s . pl . Parts of the projected meridian, according to Mercat or's system, corresponding to each minute of latitude, from the equator up to some fixed limit, usually 80°.