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).
diaphragm. 1  the partition of muscles and tendons that separates the chest cavity from the abdominal cavity; midriff. 2  any membrane or partition that separates one thing from another. 3  a dividing wall at the node of a plant stem. 4  a device to regulate the amount of light entering the lens of a camera, microscope, etc. (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.