Horizontal runs parallel to the horizon. Vertical stands perpendicular to it. 6 meanings: 1. parallel to the plane of the horizon; level; flat → Compare vertical (sense 1) 2. of or relating to the horizon.... Click for more definitions. The meaning of HORIZONTAL is of or relating to the apparent junction of earth and sky : situated near the horizon. How to use horizontal in a sentence. Horizontal definition: at right angles to the vertical; parallel to level ground.. See examples of HORIZONTAL used in a sentence.
