iron

iron — noun

1. a grey metal found in rocks and soil throughout the world. When combined with ca

1.nounB1
Definition

a grey metal found in rocks and soil throughout the world. When combined with carbon, it creates steel — a material used in everything from buildings to vehicles to everyday tools.

Example

The bridge is made of strong iron that can support heavy trucks.

collocation: made of iron

Iron ore is taken from mines and turned into steel in large factories.

collocation: iron ore

Common collocations
  • made of iron
  • cast iron
  • wrought iron
  • iron ore
  • iron and steel
  • scrap iron
Synonyms
  • steel

    a stronger alloy made from iron and carbon, not a pure metal

  • metal

    a broader category that includes iron and many other elements

Grammar Patterns

uncountable noun

Usage Note

Uncountable — do not say 'an iron' when referring to the metal. 'An iron' means the tool for clothes (sense 3) or a golf club (sense 4).

Common Mistakes

The knife is made of an iron.
The knife is made of iron.
When referring to the metal, iron is uncountable.

2. a dietary mineral that the body uses to make haemoglobin, the protein that moves

2.nounB2
Definition

a dietary mineral that the body uses to make haemoglobin, the protein that moves oxygen through the bloodstream. It is found naturally in foods such as red meat, spinach, and beans.

Example

Spinach and red meat are good sources of iron for a healthy diet.

collocation: sources of iron

Caio's doctor said he needed more iron in his meals to feel less tired.

collocation: more iron

Common collocations
  • iron deficiency
  • iron levels
  • iron-rich foods
  • source of iron
  • contains iron
  • low iron

Grammar Patterns

uncountable noun

Usage Note

Uncountable in this sense. 'An iron' never means a dose or type of this nutrient. Use 'iron' alone or with quantity phrases like 'a source of iron'.

3. an electrical household tool with a heated metal plate on the bottom that you sl

3.nounA2
Definition

an electrical household tool with a heated metal plate on the bottom that you slide over clothes to press out wrinkles.

Example

Maeve turned off the iron after finishing her shirts for the week.

collocation: turned off the iron

This steam iron works best when you use it on cotton fabric.

collocation: steam iron

Common collocations
  • steam iron
  • travel iron
  • cordless iron
  • plug in the iron
  • turn off the iron

Grammar Patterns

countable noun

Usage Note

Countable — 'an iron' and 'irons' work normally. Distinguish from sense 1 (the metal), which is uncountable.

Common Mistakes

I need to buy a new iron for my shirt.' (correct — countable sense for the device)
The gate is made of iron.' (uncountable
the metal)

4. a golf club with a slanted metal head, designed for striking the ball at medium

4.nounB2
Definition

a golf club with a slanted metal head, designed for striking the ball at medium range and guiding it toward the green.

Example

Christopher chose a seven-iron to hit the ball onto the green.

collocation: seven-iron

Folake practised with her five-iron at the driving range all morning.

collocation: five-iron

Common collocations
  • five-iron
  • seven-iron
  • nine-iron
  • set of irons
  • hit with an iron
Synonyms
  • club

    the general term for any golf club including woods, irons, and putters

Grammar Patterns

countable noun

Usage Note

Irons are numbered by their angle — a lower number (e.g. 3-iron) hits the ball farther but with a lower arc; a higher number (e.g. 9-iron) gives a shorter but higher shot.

5. a metal implement that is forged from iron, often heated for purposes such as br

5.nounC1
Definition

a metal implement that is forged from iron, often heated for purposes such as branding livestock or shaping materials.

Example

The rancher used a branding iron to mark the calves with his ranch symbol.

collocation: branding iron

The museum displays a branding iron that farmers used over a century ago.

collocation: branding iron

Common collocations
  • branding iron
  • hot iron
  • curling iron
  • soldering iron
Synonyms
  • tool

    a broader, more common term for any instrument used for work

Grammar Patterns

countable noun

Usage Note

This sense is rarer in modern everyday English but still common in historical or craft contexts like blacksmithing.

6. heavy metal chains wrapped around a prisoner's arms or legs to stop them from mo

6.nounC2
Definition

heavy metal chains wrapped around a prisoner's arms or legs to stop them from moving or running away.

Example

The prisoners were led into the court with heavy irons around their legs.

collocation: heavy irons

In the film, the captured soldiers were clapped in irons and locked in a cell.

collocation: clapped in irons

Common collocations
  • clapped in irons
  • heavy irons
  • rusty irons
  • put in irons
  • unlock the irons
Synonyms
  • shackles

    a more specific term for chains around wrists or ankles

  • chains

    a more general alternative, equally common in modern English

Grammar Patterns

always plural: irons

Usage Note

Always used in the plural form 'irons'. Never 'an iron' for this sense. This usage is mainly historical or literary.

Common Mistakes

The prisoner wore an iron on his feet.
The prisoner wore irons on his feet.
This sense is always plural.
Idioms

to be involved in several different activities or projects at the same time, hoping that at least one will succeed.

The entrepreneur has many irons in the fire — she is writing a book, starting a business, and teaching a class.

With three job interviews lined up, the graduate has plenty of irons in the fire this month.

to lift weights as a form of exercise in order to build stronger muscles.

The rugby team goes to the gym every morning to pump iron with their coach.

The trainer told the players that pumping iron would make them stronger on the field.

to take immediate advantage of an opportunity before conditions change.

The manager decided to strike while the iron was hot and offered the deal that same day.

When the client showed interest, the sales rep struck while the iron was hot and sent the contract.

to control people in a very strict and severe way, without allowing any disagreement.

The general ruled the country with an iron hand for over twenty years.

The head teacher ruled the school with an iron fist, and the students were afraid to break any rules.

To be involved in many different activities or projects at once, hoping one will succeed.

Maya has several irons in the fire, including a new job and a side business.

With three irons in the fire, Diego felt confident about his future.

To control someone or a group very strictly and harshly.

The principal ruled the school with a rod of iron, allowing no disobedience.

Did General Lee really rule his troops with a rod of iron?

iron — verb

iron — adjective

Word family

  • ironing
    nounB1
  • ironmonger
    nounC1
  • ironwork
    nounC1
  • ironclad
    adjectiveC2

Synonym discussion

Sense: noun/1

Iron is a pure chemical element, a grey metal that is the basis for making steel. The key difference learners need to know: steel is an alloy made by mixing iron with carbon, which makes it harder and stronger than pure iron. The word 'metal' is a broad category that includes iron, steel, aluminium, copper, and many others — so steel is a type of metal, and iron is a type of metal, but they are not the same thing. An 'alloy' is a mixture of two or more metals, so steel is one specific alloy made from iron. In everyday language, people say 'an iron gate' for a gate made of the pure metal iron, but 'a steel bridge' for a structure made of the stronger alloy. When you are unsure which word fits, 'metal' is the safest general choice.

Common collocations

Phrases

  • made of iron

Prepositions

Etymology

Proto-GermanicOld EnglishMiddle EnglishEnglish

Iron has been known to humans since prehistoric times. The word comes from Old English 'īsern', which later changed to 'īren' in Middle English. It can be traced back through Proto-Germanic 'īsarną' to Celtic origins, likely related to a word meaning 'strong' or 'holy'. The metal's name spread across Europe along with ironworking technology. The adjective sense meaning 'very strong' developed as a metaphor from the metal's toughness.