D defs.my
Entry 5 senses Webster, 1913

Diaphragm

/dī'-əf-rămˌ/ · Di·a·phragm · IPA /ˈdaɪəˌfɹæm/
01 n. A dividing membrane or thin partition, commonly with an opening through it.
  1. 1.
    A dividing membrane or thin partition, commonly with an opening through it.
  2. 2.
    The muscular and tendinous partition separating the cavity of the chest from that of the abdomen; the midriff.(Anat.)
  3. 3.
    A calcareous plate which divides the cavity of certain shells into two parts.(Zool.)
  4. 4.
    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.(Opt.)
  5. 5.
    A partition in any compartment, for various purposes.(Mach.)
Phrases & compounds
Diaphragm pump — one in which a flexible diaphragm takes the place of a piston.