A noun for “corpse” in The Etymologies of the 1930s derived from ON. ndagno under the root ᴹ√NDAK “slay” (Ety/NDAK), where the g vocalized to i before n and then ai became ae.
Conceptual Development: There were a couple of unrelated “corpse” words in Tolkien’s earlier writings. G. cweleg “corpse, dead body” appeared in the Gnomish Lexicon of the 1910s based on G. cwel- “fade, wither” (GL/28), clearly the equivalent of contemporaneous ᴱQ. qelet (qelekt-) of the same meaning (QL/76). ᴱN. rhanc “corpse, body of one slain in battle” appeared in Early Noldorin Word-lists of the 1920s related to the verb rhengi (rhang-) “to slay in battle” (PE13/152).
A noun appearing as N. rhanc “arm” in The Etymologies of the 1930s derived from primitive ᴹ✶ranku under the root ᴹ√RAK “stretch out, reach” (Ety/RAK). It had the irregular plural form rhengy, presumably from final -ui becoming -y, but this plural was archaic and reformed to rhenc based on normal Noldorin (and later Sindarin) plural patterns.
Conceptual Development: The Gnomish Lexicon of the 1910s had (archaic) G. †râ “arm, strength” (GL/65), clearly related to ᴱQ. rā “arm” in contemporaneous Qenya Lexicon from the early root ᴱ√RAHA “stretch forward” (QL/78). The Gnomish Lexicon also had a non-archaic word rath “the full arm, the extent of one’s arm, one’s reach — a measure = 2 feet”, apparently referring to both the arm itself and the reach of the arm, and so functioning as a unit of measure (GL/65).
Neo-Sindarin: Most Neo-Sindarin writers adapt the Noldorin word as ᴺS. ranc “arm” (plural renc) as suggested in HSD (HSD), since the unvoicing of initial r to rh was a feature of Noldorin of the 1930s but not Sindarin of the 1950s and 60s. Based on the Gnomish usage, this word might also be used as a unit of measure for an arm’s length, about 2 feet.