The continent in the Uttermost West where the Valar dwelled after the first wars with Morgoth destroyed the world as it was initially created (S/37). Its name is derived from the same root √MAN “blessed, unmarred” as the name of Manwë (PE17/162). The most common translation of this name was the “Blessed Realm” (S/62), though more precisely it describes the “unmarred” state of this land, free from the unfluence of Morgoth (PE17/162).
Tolkien elsewhere said that Aman was adapted from an (unknown) word from Valarin, meaning “at peace, in accord (with Eru)”, much as Manwë was an adaptation of Val. Mānawenūz (WJ/399). This is not incompatible with its derivation from the root √MAN, which itself may have been adopted into Primitive Elvish from Valarin.
Conceptual Development: According to Christopher Tolkien, the idea for this name first emerged from Ad. Amân, the Adûnaic name for Manwë (SD/376). In Tolkien’s earliest writings, the name for the Land of the Valar was simply ᴱQ. Valinor (LT1/70), but in later writings this became the Elvish name for this land, whereas Aman was its “proper” name (PE17/106).