焚烧 (fénshāo) is a formal, written verb meaning 'to burn something deliberately, especially for disposal' — used in contexts like burning waste, documents, or bodies. It is more specific and formal than the everyday 烧 (shāo), and unlike 燃烧 (ránshāo) which describes the process of burning or figurative passion, 焚烧 focuses on the deliberate act. 烧毁 (shāohuǐ) additionally implies destruction by fire.