Cultural diffusion refers to the spread of cultural items, such as ideas, styles, religions, technologies, and languages, between individuals, whether within a single culture or from one culture to another. It is distinct from the diffusion of innovations within a specific culture. Cultural diffusion can happen in many ways, including:

• Migration: Migrating populations will carry their culture with them.

• Trans-cultural visitors: Ideas can be carried by trans-cultural visitors, such as merchants, explorers, soldiers, diplomats, slaves, and hired artisans.

• Technology diffusion: Technology diffusion has often occurred by one society luring skilled scientists or workers by payments or another inducement.

• Trans-cultural marriages: Trans-cultural marriages between two neighboring or interspersed cultures have also contributed.

There are several types of cultural diffusion, including:

• Relocation diffusion: The spread of cultures that happens when people migrate to different places in the world.

• Expansion diffusion: The spread of a cultural trend through a population in a way that the number of those influenced grows continuously larger.

• Contagious diffusion: The spread of a cultural trend through a population in a way that the number of those influenced grows continuously larger.

• Hierarchical diffusion: The spread of a cultural trend from one key person or node of authority or power to other persons or places.

• Stimulus diffusion: The spread of an underlying principle, even though a specific characteristic is rejected.

• Maladaptive diffusion: The negative consequences that may arise from the adoption of a cultural trait by a society that is not well-suited to it.

Cultural diffusion has played a significant role in human history, and examples of ideas that spread via cultural diffusion include philosophy, religion, fashion, language, and technology.