A vertical is an alignment in which the top is always above the bottom. It is a property of two or more points in which if a point is directly below the second point, and they are vertical to each other. For instance, two balls are such that if the top one falls, it will always fall on the bottom one no matter what is the distance between the two balls, then the two balls are said to be vertical.
So any line or object that is moving upright or downright is vertical. Given below are some examples of vertical:
A different way of looking at vertical is through horizontal. Vertical lines or objects are always perpendicular to the horizontal lines or objects. Some examples are shown below:
Movement can also be vertical; if we say that the motion is vertical, it means the direction of movement is top-down or bottom-up.
Vertical lines in math
In math, the y-axis is considered vertical. Hence any line parallel to the y-axis is a vertical line. Also, vertical lines are perpendicular to the x-axis.
Given below are some examples.
Line L in the given picture is vertical as it is parallel to the y-axis.