umbo, umbon noun "hill, lump, clump, mass" (PE17:93)
Quenya
ambo
hill, rising ground
ambona
noun. hill
umbo
hill, lump, clump, mass
amun
hill
amun (amund-) noun "hill" (LT2:335; in Tolkien's later Quenya ambo)
oro
mount, mountain
oro (1) noun "mount, mountain" (PE17:64), cf. Qenya oro noun "hill" (LT1:256; rather ambo in LotR-style Quenya, though #oro "mountain, hill" appears in Orocarni and orofarnë, q.v. [PE17:83], also with the meaning "high" in oromar, q.v.) Cf. oro- element "up, aloft" (PE17:64).
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".
tundo
hill, mound
tundo noun "hill, mound" (TUN)
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.