# selenium

/səˈɫiniəm/ (US) · /sɛlˈiːniəm/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/selenium
Updated: 2026-05-19

## Definition

a chemical element that is a metal but is usually found in a solid form. It is used to make glass and to protect against certain types of damage to your body.

For teachers: a nonmetallic chemical element with the symbol Se and atomic number 34. It is used in the production of glass, semiconductors, and as an essential trace mineral in biological systems.

## Examples

- Selenium is an important mineral for healthy hair and nails.
- The glass manufacturer added selenium to the mixture to give the glass a deep red color.
- While selenium is vital for the proper functioning of the immune system, excessive exposure to the element can lead to toxic effects on the nervous system and skin.

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