Diffusion (noun)

1. The spreading of something more widely.
2. The gradual spread of people, ideas, or culture from one place to another.
3. The spreading of a substance, such as a gas, through a medium, especially by molecular movement.
4. The process by which heat, light, or a fluid is spread evenly through a medium or through space.

Origin:

Derived from the latin word 'diffusus' meaning 'spread out'.

Examples:

1. The diffusion of knowledge has been greatly facilitated by the internet.
2. The diffusion of English as a global language has had a profound effect on the world.
3. The diffusion of oxygen into the bloodstream is essential for life.
4. The diffusion of light through a crystal is a key factor in the creation of lasers.
5. The diffusion of heat through a metal bar is an important factor in many engineering applications.