This paper works to summarize the ways to define terms from current political affairs when they are included in the revised edition of Modern Chinese Dictionary. Since the 18th National Congress of the Communist Party of China, the Party Central Committee with Comrade Xi Jinping at its core put forward a series of new ideas, new thoughts and new strategies, and correspondingly employed a large number of terms with rich connotations. The 7th edition of Modern Chinese Dictionary had made great efforts to include them in this new edition. The paper shows that conceptual metaphor plays an important role when these terms are used in current political affairs, and summarizes three principles in defining these terms: metaphorical explanation based on parallelism between source and target domains, provision of literal meaning for the purpose of easy understanding, and clarification of the context for metaphorical interpretation.