A word in The Etymologies of the 1930s glossed “straight line, road” under the root ᴹ√TEÑ “line, direction” (Ety/TEÑ).

Neo-Quenya: For purpose of Neo-Quenya I assume its primary meaning is a simple straight line and is used for “road” only metaphorically, with the further implication that the road is straight. Since Tolkien changed the meaning of √TEÑ to “signify”, I further assume tea “straight line” is derived from *tegā based on the later root √TEG “line”.