As-salāmu ʿalaykum (Arabic: السَّلَامُ عَلَيْكُمْ‎‎ [asːaˈlaːmu ʕaˈlaikum]) is a greeting in Arabic that means “peace be upon you”. The greeting is a standard salutation among Muslims and is routinely used whenever and wherever Muslims gather and interact, whether socially or within worship and other contexts. ^[1] The typical response to the greeting is waʿalaykumu s-salām (وَعَلَيْكُم السَّلَام [waʕaˈlaikumu sːaˈlaːm]; “and upon you, peace”).

This greeting appears in greatly abbreviated forms in many languages from Malagasy to Urdu as some variant of salām (سَلَام; cf. Persian سلام [sæˈlɒːm]).

Source: As-salamu alaykum – Wikipedia