lexicow

intersect

/ˌɪntərˈsekt//ˌɪntəˈsekt/·verb

to cross at a point and continue; to have a point or area in common

I watch a car come along the flat road and another drop down the road that crosses it. For one instant they share the very same square of ground, and the junction flares as each goes through. Then they are past it, each still on its first heading — one rolling on to the right, the other on down. They needed that one point in common, and nothing more.
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Definition

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.

Examples

  • Two straight roads intersect at the town square, and each stream of traffic continues out the far side.
  • Once two paths intersect, they diverge again and may never cross a second time.
  • Her research intersects with public health wherever access to clean water is studied.

Collocations

intersect at a point· lines intersect· intersect with· the point of intersection· roads intersect

Synonyms

cross· meet· converge· overlap· traverse

Antonyms

diverge· run parallel

Word family

intersection (noun)· intersecting (adjective)

In TOEFL & IELTS

Keep the verb and noun straight: things intersect (verb), and the place they cross is an intersection (noun) — there is no 'an intersect'. Do not confuse it with intercept (to cut something off in transit, or where a line crosses an axis: the x-intercept). The tell: intersect is line-meets-line, intercept is line-meets-axis. In academic writing the figurative 'X intersects with Y' — where two fields or interests overlap — is precise and valued.

FAQ

What is the difference between 'intersect' and 'intersection'?
Intersect is the verb — the action of crossing ('the two roads intersect'). Intersection is the noun — the place or point where they cross, and in American English the road junction itself. You cannot write 'an intersect'; the thing is an intersection. Same root, different jobs: one names the action, the other the result.
What is the difference between 'intersect' and 'intercept'?
To intersect is for two things to cross each other — mutual, and both carry on. To intercept is to cut something off in transit (intercept a pass, a message), or, in maths, the point where a line crosses an axis (the y-intercept). The quick tell: intersect is line meeting line; intercept is line meeting an axis, or one thing stopping another.
What is the point where two lines intersect called?
The point of intersection — the single spot two lines share, like the junction in the scene above. Two straight lines that are not parallel intersect at exactly one point; parallel lines never intersect at all. In coordinate geometry it is where their equations give the same x and y.
Is it 'intersect' or 'intersect with'?
Both are correct. 'The two roads intersect' and 'the road intersects with the highway' are equally fine, and the with-form is especially common in the figurative sense — 'his work intersects with economics'. What you cannot say is 'intersect to'. When two things cross each other equally, you can drop the with; when one meets another, with reads naturally.
What does intersect mean in maths (sets)?
For two sets, to intersect is to have members in common — their intersection (written A ∩ B) is the collection of elements that belong to both. If the sets share nothing, their intersection is empty. In geometry the same word means curves crossing; in both, it is about what two things hold jointly.
What does it mean when two things intersect figuratively?
That two areas, interests, or identities overlap — 'where art intersects with commerce', 'their careers intersected briefly'. It is a favourite of academic writing because it names a genuine overlap without claiming one thing caused the other. (The sociology term intersectionality grew from this traffic-junction image, but that is a topic in its own right.)