a group or mass of distinct or varied things, persons, etc.: an aggregation of complainants. 2. collection into an unorganized whole. 3. the state of being so collected. 4. Biology, Ecology. a group of organisms of the same or different species living closely together but less integrated than a society.
Not to be confused with Pelvic Diaphragm. In optics, a diaphragm is a thin opaque structure with an opening (aperture) at its center.The role of the diaphragm is to stop the passage of light, except for the light passing through the aperture.Thus it is also called a stop (an aperture stop, if it limits the brightness of light reaching the focal plane, or a field stop or flare stop for other uses of diaphragms in lenses).he role of the diaphragm is to stop the passage of light, except for the light passing through the aperture. Thus it is also called a stop (an aperture stop, if it limits the brightness of light reaching the focal plane, or a field stop or flare stop for other uses of diaphragms in lenses).
The diaphragm functions in breathing. During inhalation, the diaphragm contracts and moves in the inferior direction, thus enlarging the volume of the thoracic cavity (the external intercostal muscles also participate in this enlargement).tructure [edit]. The diaphragm is a dome-shaped structure of muscle and fibrous tissue that separates the thoracic cavity from the abdomen. The dome curves upwards. The superior surface of the dome forms the floor of the thoracic cavity, and the inferior surface the roof of the abdominal cavity.