at right angles to the vertical; parallel to level ground.
flat or level: a horizontal position.
being in a prone or supine position; recumbent: His bad back has kept him horizontal for a week.
near, on, or parallel to the horizon.
of or pertaining to the horizon.
measured or contained in a plane parallel to the horizon: a horizontal distance.
(of material on a printed page, pieces on a game board, etc.) extending across, from the left to the right of the viewer.
of or pertaining to a position or individual of similar status: He received a horizontal promotion to a different department, retaining his old salary and title.
of or pertaining to companies, affiliates, divisions, etc., that perform the same or similar functions or produce the same or similar products: Through horizontal mergers the company monopolized its field.
—n.
anything horizontal, as a plane, direction, or object.