# cobalt

/ˈkoʊˌbɔɫt/ (US) · /kˈəʊbɒlt/ (UK)

Source: https://englishreference.com/word/cobalt
Updated: 2026-08-08

## Senses

### 1. the chemical element

noun · CEFR C1 · Technical

a hard, silver-grey metal used in batteries and to make strong steel.

For teachers: a hard, lustrous, silver-grey metallic element used in high-strength alloys and lithium-ion batteries. Uncountable in its elemental sense.

- Cobalt is an essential component in the batteries used for electric cars.
- The global demand for cobalt has surged due to its critical role in the production of rechargeable batteries for portable electronics.

### 2. the colour

noun · CEFR B2

a deep, bright blue colour.

For teachers: a deep, vivid blue pigment or colour, traditionally derived from cobalt salts.

- The artist used a touch of cobalt to paint the evening sky.
- The ceramicist applied a cobalt glaze to the porcelain, which turned a brilliant blue after being fired in the kiln.

### 3. deep blue

adjective · CEFR B2

having a deep, bright blue colour.

For teachers: denoting a specific shade of deep, intense blue. Often used to describe fashion, decor, or natural features.

- She wore a cobalt dress that matched the colour of her eyes.
- The interior designer recommended cobalt tiles for the bathroom to create a bold, modern aesthetic.

## Examples

- The artist used cobalt to paint the deep blue sky.
- Manufacturers require large amounts of cobalt to produce the rechargeable batteries found in modern electric vehicles.
- The transition to renewable energy has significantly increased the global demand for cobalt, leading to intensified mining operations in regions with rich mineral deposits.

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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.