A Sindarin name for the world appearing only in the name Mîr n’Ardhon “Jewel of the World” (PM/348). Since this name is the translation of Q. Ardamírë, it follows that Ardhon may be a cognate of Q. Arda: “The World, (lit.) Realm”. As such, it may be a combination of some form of S. gardh “region” (in early writings, N. ardh) with a suffixal element -on, possibly the augmentative suffix -on². It is also possible that this form is lenited, and the proper form is gardhon.