This root was the basis for Elvish words having to do with “running” and (in earlier notes) “rolling” for much of Tolkien’s life. It first appeared as ᴱ√NORO “run, go smoothly, ride, spin” in the Qenya Lexicon of the 1910s (QL/67), and it had derivatives in the contemporaneous Gnomish Lexicon such as G. nor- “run, roll” (GL/61) and dronn “race, course, track” < ✱n’rond- (GL/31). ᴹ√NORO “run as of wheels, roll along” reappeared in a page of roots in the Quenya Verbal System (QVS) from 1948, though this page was deleted (PE22/127 note #152). √NOR “run (or leap: of animals, men etc.)” also appeared in some etymological notes associated with The Lord of the Rings, probably from the late 1950s (PE17/168).
Neo-Eldarin: For purposes of Neo-Eldarin, I’d retain both senses “run” and “roll” for this root, but limit the latter to the rolling of wheels as an extrapolation from the movement of legs.
As the basis for “father” words, √AT and its extended form √ATAR date all the way back to Tolkien’s earliest ideas. The root itself did not explicitly appear in the Qenya or Gnomish Lexicons of the 1910s, but forms like ᴱQ. atar, G. †ador “father” indicate its presence (QL/33; GL/17). The root ᴹ√ATA “father” did appear in The Etymologies of the 1930s with derivatives ᴹQ. atar, N. adar (Ety/ATA) and the base √AT(AR) “father” was mentioned again in late 1960s notes on Eldarin Hands, Fingers and Numerals (VT48/19). In this late period, the Elvish words for “father” remained Q. atar and S. adar (PM/324).