mercury

mercury — noun

1. A poisonous metallic element with a shiny silver look that stays liquid at norma

1.nounB2
Definition

A poisonous metallic element with a shiny silver look that stays liquid at normal room temperature. It was once common in thermometers, though safer materials are now preferred.

Example

The old thermometer contained a small amount of mercury, which could be dangerous if it leaked.

uncountable noun for a chemical substance

Scientists now use safer liquids instead of mercury in most school thermometers.

Common collocations
  • mercury thermometer
  • mercury spill
  • mercury poisoning
  • contain mercury
  • levels of mercury
Synonyms
  • quicksilver

    an old poetic or literary name for mercury; rarely used in modern science or everyday English

Usage Note

Frequently used as an uncountable noun. Its chemical symbol is Hg, short for the Latin name hydrargyrum.

Common Mistakes

The doctor used a mercury to take my temperature.
The doctor used a mercury thermometer to take my temperature.
'mercury' is a substance, not a tool; the tool is a 'mercury thermometer'.

2. The planet in our solar system that is closest to the sun. It has a surface cove

2.nounA2
Definition

The planet in our solar system that is closest to the sun. It has a surface covered with craters and is the smallest of the eight planets.

Example

Mercury is so close to the sun that its surface can get hot enough to melt lead.

Mercury as a proper noun and planet name

Jisoo pointed her telescope at the evening sky and spotted the tiny dot of Mercury near the horizon.

Common collocations
  • the surface of Mercury
  • a mission to Mercury
  • the orbit of Mercury

Usage Note

Always capitalised as a proper noun. The Romans named the planet after their messenger god (sense 3) because it moves quickly across the sky.

Common Mistakes

The element mercury is the closest planet to the sun.
Mercury is the closest planet to the sun.
the planet name is capitalised; the chemical element is not.

3. In ancient Roman stories, the god who acted as a messenger for the other gods an

3.nounB1
Definition

In ancient Roman stories, the god who acted as a messenger for the other gods and who protected trade, travel, and merchants. He is usually shown wearing a winged hat and sandals.

Example

In Roman mythology, Mercury wore winged sandals so that he could fly quickly between the gods.

proper noun for a mythological figure

The stone statue in the town square showed Mercury holding a staff with two snakes wrapped around it.

Common collocations
  • the god Mercury
  • the temple of Mercury
  • Mercury the messenger
Synonyms
  • Hermes

    the Greek equivalent of Mercury; Hermes has the same role but belongs to Greek mythology

Usage Note

Always capitalised as a proper noun. The Greek equivalent of Mercury is Hermes. The planet Mercury (sense 2) was named after this god.

Common Mistakes

Mercury is the Greek god of travel.
Mercury is the Roman god of travel. The Greek equivalent is Hermes.
Mercury belongs to Roman mythology, not Greek.

4. The silver-coloured line or column inside a thermometer that rises or falls to i

4.nounB2
Definition

The silver-coloured line or column inside a thermometer that rises or falls to indicate the temperature. The word refers to the liquid mercury that was traditionally used in thermometers.

Example

Mira checked the mercury in the outdoor thermometer and saw that it had dropped below zero.

the mercury + dropped / rose for temperature change

The doctor tapped the thermometer gently to bring the mercury back down before taking a new reading.

Common collocations
  • the mercury rises
  • the mercury drops
  • the mercury stands at
  • check the mercury

Usage Note

Used with verbs of movement such as 'rise', 'drop', 'fall', and 'climb' to describe changes in temperature. This is a metonym — the substance (mercury) stands for the measurement it shows.