ᴺS. [N.] ^ranc n. “arm” (Category: Arm)
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 Hiswelókë’s Sindarin Dictionary (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.
References ✧ Ety/RAK
|rhenc||plural||✧ Ety/RAK: usual plural|
|ON. ranko > rhanc||[raŋko] > [raŋkʰo] > [raŋxo] > [raŋx] > [r̥aŋx] > [r̥aŋk]||✧ Ety/RAK|
|ON. rankui > †rhengy||[orkui] > [raŋkʰui] > [raŋxui] > [reŋxui] > [r̥eŋxui] > [r̥eŋgui] > [r̥eŋgy]||✧ Ety/RAK|
Reference ✧ GL/65 ✧ “arm, strength”