In this Article. In this Article. A solitary pulmonary nodule (SPN) is a single abnormality in the lung that is smaller than 3 cm in diameter. Generally, a pulmonary nodule must grow to at least 1 cm in diameter before it can be seen on a chest X-ray.
Osmosis is the scientific process of transferring fluid between molecules. When molecules move in and out of a cell to achieve the same concentration of something, like salt, on both sides, then osmosis is happening.
osmosis. 1  Physical Chemistry, Cell Biology. the tendency of a fluid, usually water, to pass through a semipermeable membrane into a solution where the solvent concentration is higher, thus equalizing the concentrations of materials on either side of the membrane. the diffusion of fluids through membranes or porous partitions. Compare endosmosis, exosmosis.