| Term | Meaning |
| Inference engine | The inference engine can be seen as the “logic” within an expert system. It uses information stored in the knowledge base to formulate a line of reasoning leading to the solution of the problem.13 |
| Knowledge base | The knowledge base is a database where all the information an expert system uses resides. A knowledge base contains both factual and heuristic knowledge (ie, knowledge which is widely known and knowledge obtained by experience in the field).13 |