diaphragm

noun

di·​a·​phragm ˈdī-ə-ˌfram 

1

: a body partition of muscle and connective tissue

specifically : the partition separating the chest and abdominal cavities in mammals

2

: a dividing membrane or thin partition especially in a tube

3

a

: a more or less rigid partition in the body or shell of an invertebrate

b

: a transverse septum in a plant stem

4

: a device that limits the aperture of a lens or optical system compare iris diaphragm

5

: a thin flexible disk (as in a microphone or loudspeaker) that vibrates when struck by sound waves or that vibrates to generate sound waves

6

: a molded cap usually of thin rubber fitted over the uterine cervix to act as a mechanical contraceptive barrier

diaphragmatic

ˌdī-ə-frə(g)-ˈma-tik 

-ˌfrag-

adjective

diaphragmatically

ˌdī-ə-frə(g)-ˈma-ti-k(ə-)lē 

adverb

Examples of diaphragm in a Sentence

Recent Examples on the Web

This enables the diaphragm to maintain accurate piston motion, reduce unwanted deformation and suppress residual vibration after the signal stops. — Mark Sparrow, Forbes.com, 10 July 2026

Soundcore Liberty 5 Noise Cancelling Earbuds The Soundcore Liberty 5 drops cinematic sound directly onto your travel kit by embedding official multi-directional Dolby Audio processing inside dual wool paper diaphragm drivers. — Juhi Wadia, PC Magazine, 6 July 2026

The abdomen may significantly protrude, pushing the diaphragm upward and making breathing more difficult. — Jennifer Borresen, USA Today, 3 July 2026

This includes titanium diaphragms for smoother high frequencies and more responsive neodymium magnets instead of traditional ferrite. — New Atlas, 8 June 2026

Word History

Etymology

Middle English diafragma, borrowed from Late Latin diaphragma, borrowed from Greek diáphragma "partition, barrier, partition of tissue separating organs," from diaphrak-, stem of diaphrássein "to divide off, separate" (from dia- dia- + phrássein, Attic phráttein "to fence in, enclose, block," of obscure origin) + -ma, resultative noun suffix

First Known Use

14th century, in the meaning defined at sense 1

Phrases Containing diaphragm

• iris diaphragm

Rhymes for diaphragm

• abram
• ashram
• buckram
• doorjamb
• exam
• goddam
• grandam
• priam
• program
• programme
• wolfram
• abraham

Kids Definition

diaphragm

noun

di·​a·​phragm ˈdī-ə-ˌfram 

1

: a sheet of muscle that separates the cavities of the chest and abdomen in mammals

2

: a device that limits the size of an opening in order to control the amount of light passing through a lens (as of a camera or microscope)

3

: a thin flexible disk that vibrates (as in a microphone)

4

: a cup-shaped device usually of thin rubber that fits over the cervix of the uterus and acts to prevent pregnancy by keeping sperm from reaching the egg

diaphragmatic

ˌdī-ə-frə(g)-ˈmat-ik 

-ˌfrag-

adjective

Medical Definition

diaphragm

noun

di·​a·​phragm ˈdī-ə-ˌfram 

1

: a body partition of muscle and connective tissue

specifically : the partition separating the chest and abdominal cavities in mammals see pelvic diaphragm, urogenital diaphragm

2

: a device that limits the aperture of a lens or optical system

3

: a molded cap usually of thin rubber fitted over the uterine cervix to act as a mechanical contraceptive barrier