What does Bismillah mean?

Bismillah means “in the name of God”. Muslims say it before beginning almost any act: eating, drinking, entering a house, starting a journey, or beginning work. The full form, Bismillah ir-Rahman ir-Rahim, “in the name of God, the Most Gracious, the Most Merciful”, opens every chapter of the Quran except one. The phrase is a reminder that the action is done with God’s permission and for his sake, and the Prophet, peace be upon him, taught that an act begun without it lacks blessing. It is written at the top of letters and books across the Muslim world. The source glossary explains the names of God it contains.