18. Purchasing power parity

19. Economic Growth

20. Physical capital

21. Human capital

22. Technological knowledge

23. Institutions

24. Economic System

25. Command Economy

26. Market Economy

27. Invisible Hand Theory

28. Property Rights

29. Economies of scale

30. Catch Up Growth

31. Cutting Edge Growth

32. Productivity

33. Marginal Product of capital

34. Law of Diminishing Returns

35. Capital stock

36. Investment

37. Depreciation

38. Steady State

39. Non-rivalrous

40. Spillover benefits (positive externality)

41. Conditional Convergence