A root in the Qenya Lexicon of the 1910s glossed “curve, bend” with derivatives ᴱQ. okka “knee” and ᴱQ. oqi “snake” (QL/70). G. octha “knee” from the contemporaneous Gnomish Lexicon is clearly related (GL/62). There are plenty of other roots for “bend” in Tolkien’s later writings, but this root remains popular as the basis for Neo-Eldarin “knee” words.