Horizontal means going left and right. This is the opposite of vertical, which means going up and down. Example: This sentence is written horizontally. It might help to know that the horizon is the farthest limit of the earth that can be seen from a given point.owever Vertical is perpendicular to horizontal. Horizontal (left to right or the x axis on a grid) Ve â¦ rtical (up to down or the y axis on a grid) The opposite of left to right is right to left. the opposite of y is-y. 8 people found this useful.