mindon (“isolated hill”) + luin (#Dor. “pale, #blue”)
Noldorin
mindolluin
place name. Mindolluin
Sindarin
mindolluin
place name. Towering Blue-head
Mindolluin
noun. pale, #blue hill
Quenya
Mindolluin
blue tower
Mindolluin noun *"Blue Tower" (mindon + luin), name of a mountain. (Christopher Tolkien translates the name as "Towering Blue-head" in the Silmarillion Index, but this seems to be based on the questionable assumption that it includes the Sindarin element dol "head, hill". Unless this translation is given in his father's papers, the name is better explained as a Quenya compound.)
Beware, older languages below! The languages below were invented during Tolkien's earlier period and should be used with caution. Remember to never, ever mix words from different languages!
Qenya
taras mindolluin thāra ondoresse
Mt. Mindolluin stands in Gondor
The mountain on which Minas Tirith was built (LotR/751), translated “Towering Blue-head” in Tolkien’s “Unfinished Index” of The Lord of the Rings (RC/439). It is a combination of a shortened or root form of minas “tower” with dol(l) “head” and luin “blue” (SA/minas, dol, luin).
Conceptual Development: In Lord of the Rings drafts from the 1940s, this name first appeared as N. Tor-dilluin, perhaps beginning with N. taur “high” (as suggested by Roman Rausch, EE/3.6), but it was soon revised to N. Mindolluin (WR/80).