The term "intersect" means to meet, cross, or overlap.
lines, rays, line segments
For lines, rays, and line segments, intersect means to meet or cross. When two lines, rays, or line segments intersect, they have one common point.
The blades on the windmill represent line segments that intersect, or cross. When two lines, rays, or line segments intersect, they have one common point; in this case, the intersect is at the center of the windmill's blades.
In the figure below, point (3,4) is the intersection of line x = 3 and line y = 4. The point can be located by starting from the origin then following the red arrows on the grid.
other geometric figures
For other geometric figures, the term "intersect" means to overlap or cross at more than one point. For example, when two planes intersect they meet at a line.
It is also possible for sets to intersect or share common elements. The Venn diagram below shows the intersection of multiples of 2 and 3 within the set of whole numbers from 1 to 12.
See also parallel lines, parallel plane.