The 1874 RLDS edition twice misspelled the name Cezoram as Cezorum, here in Helaman 6:15 and later in verse 19:
The subsequent RLDS edition (1892) maintained this error, but the 1908 RLDS edition restored the correct Cezoram. Earlier in the text, when this name is first mentioned, the name was spelled correctly in those first two RLDS editions:
The original manuscript is not extant for any of the three occurrences of this name, but the printer’s manuscript consistently reads Cezoram. The critical text will maintain this spelling.
This name appears to be a compound containing the name Zoram. Notice that the text has the name Seezoram, who was also a chief judge (Helaman 9:23, 26–27). The names Cezoram and Seezoram seem to parallel each other. The text has three different individuals named Zoram and two different peoples referred to as Zoramites. As with the name Cezoram, there was some minor tendency in the manuscripts to replace the correct spelling Zoram with Zorum; see the discussion under 1 Nephi 4:35.
Summary: The spelling Cezoram, with a as the final vowel, is the reading of the earliest extant textual sources and will be maintained in the critical text; this spelling is supported by the spelling of the names Seezoram and Zoram.