# jammer

/ˈdʒæmɝ/ (US) · /dʒˈæmɐ/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/jammer
Updated: 2026-05-28

## Definition

a device that blocks or interferes with radio signals. It is often used to stop people from using their phones or other electronic equipment in a specific area.

For teachers: an electronic device designed to disrupt or block radio frequency communications. Often used in security contexts to prevent unauthorized transmissions or in military operations to disable enemy sensors.

## Examples

- The police used a cell phone jammer to stop the criminals from calling for help.
- Security personnel installed a GPS jammer at the facility to prevent unauthorized tracking of the vehicles entering the site.
- While the jammer effectively blocked the drone's control signals, it also inadvertently interfered with the emergency radio frequencies used by the local fire department, highlighting the risks of such technology in civilian airspace.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.