WARNING: Antidepressant medications are used to treat a variety of conditions, including depression and other mental/mood disorders. These medications can help prevent suicidal thoughts /attempts and provide other important benefits.
Definition of parallel for Students. 1  1 : a line or surface that lies at or moves in the same direction as another but is always the same distance from it. 2  2 : one of the imaginary circles on the earth's surface running in the same direction as the equator and marking latitude.
Definition. Parallel lines are two lines that are always the same distance apart and never touch. In order for two lines to be parallel, they must be drawn in the same plane, a perfectly flat surface like a wall or sheet of paper. Parallel lines are useful in understanding the relationships between paths of objects and sides of various shapes.