# positron

/ˈpɑzəˌtɹɑn/ (US) · /pˈɒsɪtɹˌɒn/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/positron
Updated: 2026-10-16

## Definition

a tiny particle that is like an electron but has a positive electric charge.

For teachers: the antiparticle of the electron, identical in mass but carrying a positive charge. Annihilates on contact with an electron, producing gamma-ray photons.

## Examples

- A positron has the same mass as an electron.
- Doctors use positrons in PET scans to create detailed images of activity inside the brain.
- When a positron meets an electron, both particles vanish in a flash of gamma rays, a process physicists exploit to probe materials and image living tissue.

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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.