Osmosis deals with the flow of water. In layman's term, the water flows through a semipermeable layer of a substance such as an organism, which usually has lower concentration and flows outward to an area that has a higher concentration.
An example of osmosis in the kitchen:
ever put rice into water. The rice absorbs the water and the rice expands while the water levels decrease.
As for osmium, Os, that is an element on the periodic table.
All that to say, osmium and osmosis are not related and have nothing to do with each other.
Hopefully this helped and made sense.