intersection

Everyday

1. A place where two or more roads meet or cross; a crossroads or junction. tree →
2. (maths) The point or line where two lines or shapes cross. tree →
3. (maths) In sets and Venn diagrams, the part where two sets overlap: the things that belong to both. tree →

In the lessons

In road safety, intersections are where you must stop, look and cross carefully. In maths, the intersection of two lines is a point; in a Venn diagram, it is the middle where circles overlap. Phrases: «at the intersection», «the point of intersection», «busy intersection».

Examples

• Wait for the green man at the busy intersection. tree →
• Turn left at the next intersection. tree →
• The two lines meet at the point of intersection. tree →
• In the Venn diagram, children who like cats and dogs go in the intersection. tree →
• The intersection of the sets {1, 2, 3} and {2, 3, 4} is {2, 3}. tree →
• There is a traffic light at every intersection on our street. tree →
• Two straight lines that cross have exactly one intersection. tree →

Note

Countable; plural «intersections». Verb «intersect». In the UK people often say «junction» or «crossroads» for a road intersection. In maths sets, the intersection is the overlap («and»), not putting everything together (that is the «union»).