Influence refers to the capacity to have an effect on the character, development, or behavior of someone or something.
Common usages of influence include:
1. Social influence - how individuals change their behavior to meet the demands of a social environment
2. Cultural influence - the impact of one culture on another
3. Political influence - the ability to affect political decisions
4. Economic influence - the power to affect economic conditions
5. Sphere of influence - a territorial area over which a state or organization has significant cultural, economic, military or political influence