incident

incident — adjective

1. describes a ray of light, a wave, or a moving object that meets or strikes a sur

1.adjectiveC1
Definition

describes a ray of light, a wave, or a moving object that meets or strikes a surface.

Example

The incident light hits the water at an angle, and some of it bends downward.

collocation: incident light

Valentina measured the angle between the incident ray and the mirror in the lab.

collocation: incident ray

Common collocations
  • incident light
  • incident ray
  • incident wave
  • incident beam
  • incident particle
Synonyms
  • incoming

    less precise, describes something moving toward a point rather than striking a surface

  • falling upon

    descriptive phrase, not a single-word synonym; more general

Antonyms
  • reflected

    light that bounces off rather than striking the surface first

  • emitted

    light that leaves a source rather than arriving at a surface

Grammar Patterns

incident + noun

Usage Note

Always used before a noun (attributive). Most common in physics contexts with words like 'light', 'ray', 'wave', or 'beam'. Outside technical writing, this sense is very rare.

Common Mistakes

The incident lightened the room.
The incident light entered the room through the window.
'Incident light' is a fixed technical term; do not separate 'incident' from the noun 'light'.

incident — noun

Word family

Synonym discussion

Sense: noun/1

Incident, event, occurrence, episode, and happening all refer to something that takes place. Event is the broadest and most neutral term — it can describe anything from a birthday party to a historical moment. Incident often carries a slightly negative tone, suggesting an unusual, unpleasant, or noteworthy situation (e.g., 'a racial incident at the office'). Occurrence is the most factual and formal, commonly used in written reports or science. Episode marks a single event within a longer series, like a brief period of illness or a chapter in someone's life. Happening is the most informal and often implies something unexpected or surprising. Use incident when the event is specific and has some emotional or official weight; use event for neutral references; use episode when the event is part of a broader pattern.

event ↗occurrence ↗episode ↗happening ↗

Common collocations

Phrases

  • without incident

Etymology

LatinFrenchEnglish

From Latin 'incidere', a combination of 'in-' (upon, into) and 'cadere' (to fall). The literal meaning was 'to fall upon' — something that 'befalls' a person or happens to them. In the 1400s it entered English to mean 'something that happens or occurs.' The technical physics sense of a ray or wave striking a surface developed in the 1600s, keeping the original image of something 'falling upon' a surface.