umbo, umbon noun "hill, lump, clump, mass" (PE17:93)
Quenya
umbo(n)
noun. hill, lump, clump, mass, lump, clump, mass, hill
umbo
hill, lump, clump, mass
Túna
hill, mound
Túna (also Tún) place-name, used of the hill on which Tirion was built (Silm, TUN, KOR), derived from a stem (TUN) apparently meaning simply *"hill, mound".
ambo
hill, rising ground
ambo noun "hill, rising ground" (Markirya, PE17:92), "mount" (PE17:157), allative pl. ambonnar "upon hills" in Markirya (ruxal' ambonnar "upon crumbling hills") According to VT45:5, ambo was added to the Etymologies as a marginal note.
ambona
noun. hill
amun
hill
amun (amund-) noun "hill" (LT2:335; in Tolkien's later Quenya ambo)
tundo
hill, mound
tundo noun "hill, mound" (TUN)
A noun from 1967 notes on the comparative, apparently meaning “hill, lump, clump, mass” and derived from the root √MBŎNO (PE17/93), where the um- developed from syllabic initial ṃ-. Tolkien introduced the root √MBŎNO to serve as a new basis for S. amon “hill”, motivated by his decision to give the root √AM “up” a new meaning: √AMA “addition, increase, plus”, so that it could serve as the basis for the intensive prefix am- (PE17/91).
Neo-Eldarin: I prefer Q. an- as the basis for intensives, but I think the word umbo(n) might be worth retaining in the more limited sense “lump, clump, mass”. For “hill”, however, I’d use the better attested Q. ambo.