According to Hunter and Ferguson, the name "Cumorah" (Mormon 6:2) appears to be Hebrew. The Hebrew is written out in our script as Komaw or Qowmah, meaning "height, high, tall." The suffix at the end of Cumorah may be derived from the Hebrew term sounded out as rah-mah, the latter term also meaning "height, high." As has been pointed out, the early Jaredites used the name Ramah in referring to the Cumorah area (Ether 15:11). Thus, the two terms, Ramah and Cumorah -- one a Jaredite term for the elevation and the other a Nephite term for the same place -- are consistently descriptive of the place. In both instances the meaning is "height' or "high." [Milton R. Hunter and Thomas Stuart Ferguson, Ancient America and the Book of Mormon, p. 364]
“By a Hill Which Was Called Cumorah”
The hill Ramah was a major site in the final battles of the Jaredites. Moroni says that the hill Ramah "was that same hill where my father Mormon did hide up the records unto the Lord, which were sacred" (Ether 15:11). In Mormon 6:2 this hill is identified as the "hill which was called Cumorah."
According to Hunter and Ferguson, careful study of the Nephite account discloses that Cumorah was a place of considerable elevation. The fact that it was prominent and conspicuous enough to bear a name in both Jaredite and Hebrew-Nephite geographical terminology suggests the idea of a prominent elevation. . . . Also, the place was known to their historians for many hundreds of years as has been shown.
The question arises, if Ramah-Cumorah were an elevation of considerable height, as suggested, why then do the Book of Mormon writers refer to it as a "hill"? The interesting fact is that all mountains, regardless of size, are referred to as "hills" in the Book of Mormon. The Hebrew term "harar" is translated "hill or mountain." It is the term used for referring to large elevations. The translators of the Old Testament have sometimes rendered the term "hill" and sometimes as "mountain." Apparently Joseph Smith saw fit to render it "hill" in all instances where an elevation was referred to by name in the Nephite account. In doing so he was doing an excellent job of translating.
Thus, the expression found in the Nephite account, "hill Cumorah" would seem to refer to a mount or mountain of considerable prominence in the area where it was located. The reader should also keep in mind that the hill Cumorah was near another hill, the "hill Shim" (Ether 9:3). [Milton R. Hunter and Thomas Stuart Ferguson, Ancient America and the Book of Mormon, pp. 364-365]