The adjective taer “straight” appeared in the entry for the root ᴹ√TEÑ “line, direction” as a derivative of ᴹ✶teñrā (Ety/TEÑ). In The Etymologies as published in The Lost Road, Christopher Tolkien gave its form as tær (LR/392), but Carl Hostetter and Patrick Wynne corrected this tær, taer in their Addenda and Corrigenda to the Etymologies (VT46/18). The form taer may have replaced N. tîr “straight, right” from the earlier version of the entry {ᴹ√TEƷ} > ᴹ√TEÑ, where Tolkien derived N. tîr from tēra < ᴹ✶teñrā (Ety/TEƷ; EtcAC/TEƷ).

Conceptual Development: The Gnomish Lexicon of the 1910s had G. tîr whose archaic meaning was “†straight”, but whose later meaning was “upright, honest” or (as a noun) “esteem, regard, honour” possibly due to a blending with other roots (GL/71). Early Noldorin word-lists had ᴱN. tain “straight” derived from ᴱ✶tegnā (PE13/153, 165).

Neo-Sindarin: The best Neo-Sindarin forms for these words are unclear. 1930s N. taer seems to have an abnormal modification of the ancient vowel to ǣ so that ǣ > ai and then ai > ae. The expected Noldorin development of primitive ᴹ✶teñrā would be the vanishing of ñ (> ʒ) with lengthening the vowel to ē and then ē > ī, producing N. tîr as in the earlier version of the root’s entry.

Another complication is that in later writings, Tolkien changed the root to √TEG “line” (PE19/97), repurposing √TEÑ to mean “indicate, point to” (WJ/394; PE22/149). The expected result of primitive *tegrā is teira > tair; compare S. cail < ✶keglē. However taer might still be the Sindarin result if there was an abnormal change of the ancient e to similar-sounding ę̄ (the 1950s analog of 1930s ǣ) perhaps via a-fortification, so that [ę̄] became [ai] and then ae. This usage clashes with S. taer “lofty” from the 1950s (PE17/186), but I think the two adjectives could coexist: taer meaning “lofty” when applied to vertical things like mountains but “straight” when applied to (mostly) horizontal things like roads and lines.

I also think it is worth retaining N. tîr < *teñra < √TEÑ with an original meaning of “that which is indicated” (but no longer meaning “straight”), so that its modern Sindarin sense could be “right, *correct”. I would further assume tîr has its Gnomish meanings “upright, honest” when applied to persons, so that it means “esteem, regard, honour” when used as a noun.

If the conflict between taer “lofty” and taer “straight” bothers you too much, you might instead use tîr for both “straight” and “right, *correct” (analogous to ᴹQ. téra), though it is less clear where the sense “straight” comes from in Tolkien’s later paradigm of roots.

See N. taer for discussion.

See N. taer for discussion.

See N. taer for discussion.