# planet

/ˈpɫænət/ (US) · /plˈænɪt/ (UK)

Source: https://englishreference.com/word/planet
Updated: 2026-06-19

## Senses

### 2. the Earth

noun · CEFR B1

the world we live on, especially when talking about the environment.

For teachers: the Earth, often used in environmental or global contexts to emphasise its uniqueness or fragility.

- We must work together to protect the planet for future generations.
- The summit focused on how international policy can mitigate the damage humans have caused to the planet over the last century.

Usage: Almost always used with the definite article 'the' or the demonstrative 'this'.

### 3. historical/astrological body

noun · CEFR C2 · Archaic · Technical

in the past, any object in the sky that moved differently from the stars, including the sun and moon.

For teachers: historically, any of the seven celestial bodies visible to the naked eye that moved against the background of fixed stars.

- Ancient observers noticed that certain planets moved across the sky while stars stayed in place.
- In medieval cosmology, the Sun and Moon were classified as planets alongside Mercury, Venus, Mars, Jupiter, and Saturn.

Teaching tip: This sense is mostly found in historical texts or discussions of astrology; modern science excludes the Sun and Moon from this category.

## Examples

- Mars is known as the red planet.
- Scientists are searching for another planet in our galaxy that might support human life.
- The discovery of several rocky planets orbiting the nearby star has reignited public interest in the possibility of extraterrestrial biological signatures.

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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.