设计 (shè jì) means 'to design' or 'to plan', focusing on creating the form, function, or layout of something (e.g., a product, building, or system). It differs from 计划 (jì huà), which is a concrete action plan or schedule, and from 规划 (guī huà), which is a long-term, systematic plan for development. 构思 (gòu sī) is more about conceiving the artistic or structural idea of a creative work.