detector

detector — noun

1. An object built to locate or reveal something that would otherwise remain hidden

1.nounB1
Definition

An object built to locate or reveal something that would otherwise remain hidden — including smoke, metal, movement, or dishonest answers

Example

The smoke detector went off when the toast burned in the kitchen.

collocation: smoke detector

Airport security asked Esteban to empty his pockets before walking through the metal detector.

collocation: metal detector

Common collocations
  • smoke detector
  • metal detector
  • motion detector
  • lie detector
  • carbon monoxide detector
  • detector goes off
  • detector picks up
Synonyms
  • sensor

    A sensor detects physical input (heat, light, pressure) but does not always signal an alarm or identify a specific substance.

  • alarm

    Alarm focuses on the warning function; a detector may or may not include an audible alert.

  • scanner

    A scanner actively sweeps an area; a detector can be stationary and passive.

Usage Note

Commonly combined with the name of the substance being detected, as in smoke detector, metal detector, or lie detector.

Common Mistakes

The fire detector saved our house.
The smoke detector saved our house.
Most home safety devices detect smoke particles, not fire directly.
A detector can detection small signals.
A detector can detect small signals.
Use the verb 'detect' after a modal, not the noun 'detection'.

2. A specialized electronic device that picks up radio waves, electromagnetic field

2.nounB2
Definition

A specialized electronic device that picks up radio waves, electromagnetic fields, or radioactive particles, typically used in scientific or technical work

Example

The lab technician used a radiation detector to check for leaks near the storage room.

collocation: radiation detector

Luca pointed the wave detector at the wall and picked up a hidden listening device.

Common collocations
  • radiation detector
  • wave detector
  • signal detector
  • particle detector
  • radio-frequency detector
Synonyms
  • receiver

    A receiver specifically processes incoming signals for output; a detector only registers their presence.

  • probe

    A probe is inserted into an environment for sampling; a detector can operate at a distance.

  • Geiger counter

    A Geiger counter is a specific type of radiation detector used in labs and field work.

Usage Note

In scientific contexts this sense overlaps with sensor, but detector usually implies identifying a specific substance or energy type, whereas sensor measures a physical quantity.

Common Mistakes

The radio detector can hearing signals from far away.
The radio detector can pick up signals from far away.
Use 'pick up' or 'detect', not 'hearing'.

Word family

Synonym discussion

Sense: noun/1

Detector, sensor, alarm, scanner, and probe all refer to devices that find or respond to something, but they differ in function and context. A detector is designed to pick up a specific substance or phenomenon (smoke, metal, radiation) and often triggers a response. A sensor measures a physical quantity such as temperature, light, or pressure but does not necessarily identify a specific material. An alarm emphasizes the warning output — it may be part of a detector but can also simply sound when triggered by any input. A scanner actively sweeps an area (e.g., a barcode scanner or body scanner), while a detector can remain stationary. A probe is typically inserted into an environment to take samples or readings. For example, a smoke detector sounds an alarm when it senses smoke particles, whereas a temperature sensor only reports degrees — it does not label the source of the heat.

sensor ↗alarm ↗scanner ↗probe ↗

Common collocations

Nouns

Adverbs

Phrases

  • detector goes off
  • detector picks up
  • walk through a detector
  • install a detector
  • set off a detector

Prepositions

  • detector for
  • detector in
  • detector of
  • detector near

Etymology

LatinEnglish

Detector comes from Latin 'detegere' meaning 'to uncover or disclose' — formed from 'de-' (off, away) and 'tegere' (to cover). The verb 'detect' entered English in the early 1400s. The noun 'detector' was first used in the mid-1500s for a person who exposes something hidden. By the late 1800s it was applied to mechanical and electrical devices that reveal the presence of invisible substances or signals.