# calcium

/ˈkæɫsiəm/ (US) · /kˈælsiəm/ (UK)

Source: https://englishreference.com/word/calcium
Updated: 2026-06-20

## Senses

### 1. the mineral for health

noun · CEFR B2

a substance found in foods like milk and cheese that helps you grow strong bones and teeth.

For teachers: the chemical element considered as a dietary mineral essential for the maintenance of skeletal structure and various physiological functions.

- Drinking milk is a good way to get enough calcium for your bones.
- A diet deficient in calcium during adolescence can lead to decreased bone density and a higher risk of fractures in later life.

Usage: Usually uncountable when referring to the nutrient in food or the body.

### 2. the chemical element

noun · CEFR C1 · Technical

a soft, silver-white metal that is found in rocks like limestone.

For teachers: the alkaline earth metal with atomic number 20, occurring naturally in compounds such as limestone, gypsum, and fluorite.

- The scientist explained that calcium is a very reactive metal in its pure form.
- In its elemental state, calcium is a silvery-white metal that reacts steadily with water to form calcium hydroxide and hydrogen gas.

## Examples

- Milk is a great source of calcium for growing children.
- Doctors often recommend that older adults take a daily supplement to ensure they get enough calcium for bone density.
- The biological importance of calcium cannot be overstated, as it serves as a vital messenger in cell signaling and is the primary structural component of the vertebrate skeleton.

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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.