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Webster 1913 Edition

Diaphragm

Di′a-phragm

,
Noun.
[L.
diaphragma
, Gr. [GREEK], fr. [GREEK] to fence by a partition wall;
διά
through + [GREEK], [GREEK], to fence, inclose; prob. akin to L.
fareire
to stuff: cf. F.
diaphragme
. See
Farce
.]
1.
A dividing membrane or thin partition, commonly with an opening through it.
2.
(Anat.)
The muscular and tendinous partition separating the cavity of the chest from that of the abdomen; the midriff.
3.
(Zool.)
A calcareous plate which divides the cavity of certain shells into two parts.
4.
(Opt.)
A plate with an opening, which is generally circular, used in instruments to cut off marginal portions of a beam of light, as at the focus of a telescope.
5.
(Mach.)
A partition in any compartment, for various purposes.
Diaphragm pump
,
one in which a flexible diaphragm takes the place of a piston.

Webster 1828 Edition

Diaphragm

DIAPHRAGM

,
Noun.
Diafram. [Gr., to break off, to defend.]
1.
In anatomy, the midriff, a muscle separating the chest or thorax from the abdomen or lower belly.
2.
A partition or dividing substance.

Definition 2024

diaphragm

diaphragm

English

Noun

diaphragm ‎(plural diaphragms)

  1. (anatomy) In mammals, a sheet of muscle separating the thorax from the abdomen, contracted and relaxed in respiration to draw air into and expel air from the lungs; also called thoracic diaphragm.
  2. (anatomy) Any of various membranes or sheets of muscle or ligament which separate one cavity from another.
  3. A contraceptive device consisting of a flexible cup, used to cover the cervix during intercourse.
  4. (mechanics) A flexible membrane separating two chambers and fixed around its periphery that distends into one or other chamber as the difference in the pressure in the chambers varies.
  5. (acoustics) In a speaker, the thin, semi-rigid membrane which vibrates to produce sound.
  6. (optics, photography) A thin opaque structure with a central aperture, used to limit the passage of light into a camera or similar device.
  7. (chemistry) A permeable or semipermeable membrane
    • 1921, Wilder Dwight Bancroft, Applied Colloid Chemistry: General Theory, page 207:
      The mass of liquid transported through a porous diaphragm in a given time is directly proportional to the current.
  8. (construction) A floor slab, metal wall panel, roof panel or the like, havig a sufficiently large in-plane shear stiffness and sufficient strength to transmit horizontal forces to resisting systems.

Derived terms

Translations

Verb

diaphragm ‎(third-person singular simple present diaphragms, present participle diaphragming, simple past and past participle diaphragmed)

  1. (optics, photography) To reduce lens aperture using an optical diaphragm.
    • 1870, D. Appleton & Co., Appletons' Annual Cyclopædia and Register of Important Events of the Year 1869, page 43:
      He employs an equatorial with an object-glass having a focal length of five metres, and which was diaphragmed down to eight centimetres.
  2. To act as a diaphragm, for example by vibrating.
    • 1996, Tom Drozda et al., Tool and Manufacturing Engineers Handbook, vol. VIII: Plastic Part Manufacturing, ISBN 0872630854, page 16-24:
      The holes and burning are caused by the part diaphragming at 20000-40000 cycles/second.

Translations

Etymology

From Ancient Greek διάφραγμα ‎(diáphragma, “partition”), from διά ‎(diá, “across”) and φράγμα ‎(phrágma, “barrier”), from the verb φράσσω ‎(phrássō).

Pronunciation

  • IPA(key): /ˈdaɪəˌfɹæm/

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