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).
In the body, the diaphragm is a curved sheet of smooth muscle which  separates the thorax from the abdomen. When it contracts, the  diaphragm flattens, which INCREASES the v â¦ olume of the THORAX, which  then EXPANDS the lungs.