flat iron

noun

1

: a device used for straightening hair by pressing and pulling sections between two heated metal or ceramic, flat, rectangular plates

2

usually flatiron

ˈflat-ˌī(-ə)rn 

old-fashioned : iron sense 2a

Examples of flat iron in a Sentence

Recent Examples on the Web

Its shoulder section yields flat iron and ranch steaks, while its blade section contains the teres major, or petite tender—the third most tender muscle on the animal. — Bridget Shirvell, Martha Stewart, 18 July 2026

This one from the tried-and-true brand, Chi, is a good option for shoppers who want a no-frills flat iron that gets hot, presses away frizz, and boosts shine. — Essence Wiley, InStyle, 26 June 2026

Avoid your flat iron, hair dryer and curling iron as much as possible. — Helen Carefoot, Flow Space, 20 May 2026

L’Oréal also recently got into the hair tech game with the Colorsonic hair-dye wand, plus its own AirLight Pro hair dryer and Light Straight flat iron. — Victoria Song, The Verge, 21 Apr. 2026

Word History

First Known Use

1743, in the meaning defined at sense 2

Rhymes for flat iron

• flatiron
• gridiron

Kids Definition

flatiron

noun

flat·​iron -ˌī(-ə)rn 

: iron entry 1 sense 2c