| Term | Definition |
| Perfect Competition | Many buyers and sellers |
| Perfect Competition | No barriers to entry into or exit from the market |
| Perfect Competition | No control over price |
| Perfect Competition | Sellers sell identical products |
| Perfect Competition | No industry secrets |
| Monopoly | One seller |
| Monopoly | Complete barriers to entry into or exit from the market |
| Monopoly | Economies of Scale (mail) |
| Monopoly | Natural Monopoly (plumbing) |
| Monopoly | Technology |
| Monopoly | Government Created (patent, franchise, license) |
| Monopoly | Near total control over price by the firm |
| Monopolistic Competition | Many sellers |
| Monopolistic Competition | Few barriers to entry into or exit from the market |
| Monopolistic Competition | Little control over price |
| Monopolistic Competition | Differentiated products |
| Monopolistic Competition | Non-price product competition |
| Oligopoly | A few sellers dominate the market |
| Oligopoly | High barriers to entry into or exit from the market |
| Oligopoly | Some control over price |
| Oligopoly | Some variety of products |
| Oligopoly | Non-price product competition |
| Oligopoly | A chance to see competitive agreements among the firms |
| Oligopoly | Collusion – illegal price fixing |
| Oligopoly | Cartel – an arrangement of oligopolies to get together to fix prices or quantities of goods (doesn't last) |
| Example of Monopolistic Competition | restaurants, cereal, clothing, shoes |