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

And so in our bodies, our lungs are powered partly by our diaphragm. —Steven Strogatz, Quanta Magazine, 12 June 2025

As a dedicated low-frequency driver, this new dynamic driver has a glass speaker dome and a polyurethane diaphragm, bringing a new flavor of bass presentation while keeping all the strengths of Campfire’s dual-magnet line. —Mark Sparrow, Forbes.com, 14 Apr. 2025

The diaphragm of a smoker with lung damage will show muscle loss. —Lana Barhum, Verywell Health, 26 Feb. 2025

The microphones have 6mm diaphragms which is around one and a half times larger than the diaphragm used in the average Lavalier microphone and should capture a full and rich sound. —Mark Sparrow, Forbes.com, 24 June 2025

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

• abraham
• anagram
• cablegram
• cofferdam
• dendrogram
• diagram
• epigram
• hexagram
• histogram
• hologram
• instagram
• kilogram

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