how to name the intersection of a line and a plane
Line–plane intersection In analytic geometry, the intersection of a line and a plane in three-dimensional space can be the empty set, a point, or a line. It is the entire line if that line is embedded in the plane, and is the empty set if the line is parallel to the plane but outside it. Otherwise, the line cuts through the plane at a single point.
Chicago "L" The Chicago rapid-transit system is officially nicknamed the "L".[80] This name for the CTA rail system applies to the whole system: its elevated, subway, at-grade, and open-cut segments. The use of the nickname dates from the earliest days of the elevated railroads. Newspapers of the late 1880s referred to proposed elevated railroads in Chicago as "'L' roads."[81] The first route to be constructed, the Chicago and South Side Rapid Transit Railroad gained the nickname "Alley Elevated", or "Alley L" during its planning and construction,[82] a term that was widely used by 1893, less than a year after the line opened.[83][84]