iron

1 of 3

noun

ˈī(-ə)rn 

1

: a silver-white malleable ductile magnetic heavy metallic element that readily rusts in moist air, occurs in pure form in meteorites and combined in most igneous rocks, is the most abundant element on Earth by mass, and is vital to biological processes see Chemical Elements Table

2

: something made of iron: such as

a

: a household device usually with a flat metal base that is heated to smooth, finish, or press (such as cloth)

b

: any of a series of numbered golf clubs having relatively thin metal heads compare wood

c

irons plural : shackles for the hands or legs

d

: a heated metal implement used for branding or cauterizing

e

: stirrup

—usually used in plural

3

: great strength, hardness, or determination

iron

2 of 3

adjective

1

: of, relating to, or made of iron

2

: resembling iron

3

a

: strong and healthy : robust

an iron constitution

b

: inflexible, unrelenting

iron determination

c

: holding or binding fast

an iron grip

ironness

ˈī(-ə)rn-nəs 

noun

iron

3 of 3

verb

ironed; ironing; irons

transitive verb

1

a

: to smooth with or as if with a heated iron

iron a shirt

b

: to remove (something, such as wrinkles) by ironing

2

: to shackle with irons

3

: to furnish or cover with iron

intransitive verb

: to smooth or press cloth or clothing with a heated iron

Phrases

iron in the fire

1

: a matter requiring close attention

2

: a prospective course of action

Synonyms

Noun

• chain
• handcuff(s)
• bracelet
• bind
• confinement

Adjective

• solid
• sturdy
• strong
• firm
• vigorous

Examples of iron in a Sentence

Noun

guards forced the prisoners to sleep while still shackled in irons

Adjective

he had an iron determination to succeed in on Wall Street

Recent Examples on the Web

Noun

There, interactions between streams of liquid iron generate a magnetic field one quintillion times more powerful than that of an ordinary lab magnet (but thousands of times weaker than the Sun’s). —Literary Hub, 27 Oct. 2025

Chemical clues from another world What makes these observations particularly intriguing and puzzling is the detection of nickel without concurrent detection of iron above our instrumental limits. —Darryl Seligman, Space.com, 27 Oct. 2025

Adjective

This non-iron chino pant from Charles Tyrwhitt is guaranteed to always look its best, even with minimal care. —Christian Gollayan, Men's Health, 6 Mar. 2023

Speak to your doctor about lowering your dose of prenatal vitamins or switching to a non-iron prenatal vitamin. —Amber Smith, Discover Magazine, 8 Nov. 2022

Verb

The fabric is designed to remain smooth without ironing, and button cuffs and a chest pocket contribute to its timeless style. —Jacqueline Tempera, PEOPLE, 4 Oct. 2025

Once dry, hats-in-process undergo a second blocking to further impress the shape, and are then crown-ironed, which sees the hats spun on pads heated to 250 degrees while being brushed to ensure its fur runs in a single direction. —Eric Twardzik, Robb Report, 3 Oct. 2025

Word History

Etymology

Noun

Middle English, from Old English īsern, īren; akin to Old High German īsarn iron

First Known Use

Noun

before the 12th century, in the meaning defined at sense 1

Adjective

before the 12th century, in the meaning defined at sense 1

Verb

15th century, in the meaning defined at transitive sense 3

Phrases Containing iron

• alpha iron
• angle iron
• cast iron
• climbing iron
• curling iron
• flat iron
• ingot iron
• iron curtain
• iron gray
• iron hand
• iron horse
• iron lung
• iron maiden
• iron man
• iron out
• iron out the wrinkles
• iron oxide
• iron pyrites
• iron ration
• iron sulfide
• pig iron
• pump iron
• rule with an iron fist/hand
• rule with a rod of iron
• shooting iron
• soldering iron
• steam iron
• strike while the iron is hot
• waffle iron
• work/iron out the kinks
• wrought iron

Rhymes for iron

• flatiron
• gridiron

Kids Definition

iron

1 of 3 noun

ˈī(-ə)rn 

1

: a heavy magnetic silver-white metallic element that quickly rusts in moist air, occurs in meteorites and rocks, and is widely used see element

2

: something made of iron: as

a

plural : handcuffs or chains used to bind or hinder movement

b

: a heated metal tool used for branding

c

: a household device with a flat metal base that is heated to smooth or press cloth

3

: strength sense 1, hardness

muscles of iron

iron

2 of 3 adjective

1

: of, relating to, or made of iron

2

: resembling iron

3

: being strong and healthy : robust

an iron constitution

4

: inflexible sense 3, unrelenting

iron determination

iron

3 of 3 verb

: to smooth or press clothes with a heated iron

iron a shirt

ironer noun

Medical Definition

iron

noun

ˈī(-ə)rn 

1

: a heavy malleable ductile magnetic silver-white metallic element that readily rusts in moist air, occurs native in meteorites and combined in most igneous rocks, is the most used of metals, and is vital to biological processes (as in transport of oxygen in the body)

—symbol Fe see Chemical Elements Table

2

: iron chemically combined

iron in the blood

iron adjective