UX Concept definitions

As part of my collaboration with the Interaction Design Foundation, I wrote some definitions on several concepts that apply to User Experience design.
Here are the links below - feel free to browse the entire literature section of the IDF for more!
1. Barriers To Market Entry https://www.interaction-design.org/literature/topics/barriers-to-market-...
2. Behavioral Economics https://www.interaction-design.org/literature/topics/behavioral-economics
3. Cognitive Friction https://www.interaction-design.org/literature/topics/cognitive-friction
4. Color Theory https://www.interaction-design.org/literature/topics/color-theory
5. Design Guidelines https://www.interaction-design.org/literature/topics/design-guidelines
6. Design Principles (to be published)
7. Emotional Design https://www.interaction-design.org/literature/topics/emotional-design
8. Endowment Effect https://www.interaction-design.org/literature/topics/endowment-effect
9. Fitts’ Law https://www.interaction-design.org/literature/topics/fitts-law
10. Formal Methods (to be published)
11. Heuristic Evaluation https://www.interaction-design.org/literature/topics/heuristic-evaluation
12. Mobile UX Design https://www.interaction-design.org/literature/topics/mobile-ux-design
13. Search Engine Optimization https://www.interaction-design.org/literature/topics/search-engine-optim...
14. Social Proof https://www.interaction-design.org/literature/topics/social-proof
15. Socio-Technical Systems (to be published)
16. User Centered Design https://www.interaction-design.org/literature/topics/user-centered-design
17. User Research https://www.interaction-design.org/literature/topics/user-research
18. UX Design https://www.interaction-design.org/literature/topics/ux-design
19. UX Research https://www.interaction-design.org/literature/topics/ux-research
20. Visual Design https://www.interaction-design.org/literature/topics/visual-design