# mercury

/ˈmɝkjɝi/ (US) · /mˈɜːkjʊɹi/ (UK)

Source: https://englishreference.com/word/mercury
Updated: 2026-08-15

## Senses

### 1. the liquid metal

noun · CEFR B1 · Technical

a heavy, silver-colored metal that is liquid at room temperature.

For teachers: a heavy, silvery-white metallic element that is liquid at standard conditions; often referred to as quicksilver.

- Old thermometers used mercury to show the temperature, but modern ones are safer.
- The environmental agency issued a warning regarding high levels of mercury found in predatory fish species near the industrial site.

Usage: Uncountable when referring to the element itself; countable when referring to a column of the metal in a measuring instrument.

### 2. the planet

noun · CEFR B1

the smallest planet in our solar system and the one closest to the Sun.

For teachers: the innermost and smallest planet in the Solar System, characterized by a rocky surface and extreme temperature fluctuations.

- Mercury is very difficult to see from Earth because it stays so close to the Sun.
- Data from the space probe revealed that Mercury possesses a surprisingly strong magnetic field for a planet of its size.

Usage: Always capitalized as a proper noun.

### 3. the Roman god

noun · CEFR C1 · Literary

the Roman god of travel, business, and speed, known for his winged shoes.

For teachers: the Roman deity of commerce, travel, and thievery, serving as the messenger of the gods.

- In ancient stories, Mercury wore a winged hat and sandals to fly quickly.
- The statue depicted Mercury in a dynamic pose, emphasizing the agility and speed associated with the divine messenger.

Usage: Always capitalized as a proper noun.

### 4. a messenger

noun · CEFR C2 · Archaic · Literary

a person who carries news or messages from one place to another.

For teachers: a bearer of news or a messenger; a person who delivers tidings.

- The young mercury ran through the streets to deliver the urgent letter.
- The poet described the wind as a swift mercury, carrying the scent of rain across the parched valley.

Teaching tip: This sense is rare in modern speech; learners will mostly encounter it in 19th-century literature or classical poetry.

## Examples

- The mercury in the thermometer rises as the room gets warmer.
- Old thermometers contain mercury, which is a toxic substance that requires careful handling if the glass breaks.
- Because mercury is the only metal that remains liquid at room temperature, it has historically been used in barometers and electrical switches despite its known neurotoxicity.

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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.