Is the movement of oxygen from alveoli lungs into bloodstream an example diffusion?

Yes, the movement of oxygen from alveoli lungs into bloodstream is an example of diffusion.

Diffusion is the net movement of molecules or other small particles from a region of higher concentration to a region of lower concentration. In the case of oxygen, the concentration of oxygen is higher in the alveoli than it is in the bloodstream, so oxygen molecules will diffuse from the alveoli into the bloodstream.

The diffusion of oxygen from the alveoli into the bloodstream is an essential part of respiration. Respiration is the process by which oxygen is taken in from the atmosphere and carbon dioxide is released. The oxygen that is taken in during respiration is used by the body's cells to produce energy.