Coincide and intersect both involve a shared point, with a difference in how much is shared. Coincide is for two things to occupy exactly the same point or line, or happen at the same time — an exact overlap. Intersect is to cross at a point and continue past it. Coincide is an exact overlap; intersect is a crossing.
Both share a point, but coincide overlaps exactly and intersect merely crosses. Coincide, from co- 'together' and incidere 'to fall upon', means two things fall on exactly the same spot, line or moment — they overlap. Intersect, from inter- 'between' and secare 'to cut', means two things cross at a point and then carry on their own ways. Two lines that coincide lie exactly on top of each other; two that intersect cross at one point and diverge. One is a full overlap; the other a single crossing.
coincide
To coincide is to occupy the same point — in time, space, or opinion — while belonging to different paths. From the Latin co-incidere, 'to fall upon together'. Festivals coincide with full moons; an interview coincides with a strike; two rivals' interests briefly coincide. The word insists on independence: neither schedule bent for the other, which is exactly what makes coincidence feel like fate — two orbits, each obeying only itself, agreeing on a single moment.
intersect
To intersect is for two lines, roads, or paths to cross each other at a point and carry on past it — from the Latin inter- 'between' and secare 'to cut', literally to cut between. Where roads intersect there is a junction; where two sets intersect there are the members they share. The word runs figuratively too: two fields of study intersect where their concerns overlap. Unlike paths that meet and stop, intersecting lines cross and keep going, then diverge again beyond the point.
| coincide | intersect | |
|---|---|---|
| Meaning | occupy the same point, line or time | cross at a point and continue |
| How much shared | an exact overlap | a single crossing point |
| In geometry | lines lie exactly on each other | lines cross at one point, then part |
| Often with | dates, events, lines, opinions | roads, lines, sets, disciplines |
| Noun | coincidence | intersection |
| Example | The lines coincide. | The roads intersect. |
Ask whether two things overlap exactly or merely cross. Coincide has two things fall on exactly the same point, line or moment — an exact overlap, two rings meeting at their one shared point. Intersect has two paths cross at one point and continue their own ways. If two things overlap exactly, they coincide; if two paths cross and part, they intersect.
coincide
- iThe two lines coincide at exactly one point.
- iiHer visit happened to coincide with the festival.
- iiiOur views on the matter largely coincide.
intersect
- iThe two roads intersect at the edge of town.
- iiTheir research interests intersect at climate policy.
- iiiThe line intersects the circle at two points.
In geometry the distinction is sharp: lines that coincide lie exactly on top of one another (sharing every point), while lines that intersect cross at just one point and diverge. In everyday use, coincide stresses exact overlap in space or time, and can mean agreement; intersect stresses a crossing where two paths share common ground but continue apart.
A precise pair for maths, geography and argument. Coincide is an exact overlap — lines that coincide share every point; events that coincide happen at the same time; views that coincide agree. Intersect is a single crossing — roads intersect, sets intersect, fields of study intersect at a shared concern. Examiners reward the difference: full overlap (coincide) versus a crossing point (intersect). The nouns are coincidence and intersection.