An archaic word for “eagle” in the Gnomish Lexicon of the 1910s, related to ᴱQ. ea(r) of the same meaning (GL/51), though the exact correspondence (and sound changes) are not clear.
Gnomish
thorn
noun. eagle
thorn sir
place name. Eagle-stream
cristhorn
place name. Eagles’ Cleft
aith
noun. thorn
aithos
noun. thorn bush
aithr
noun. thorn, †sword
ior Archaic
noun. eagle
ioroth
noun. eagle
A word for “eagle” in the Gnomish Lexicon of the 1910s, an elaboration of archaic G. †ior “eagle” of the same meaning (GL/51).
A noun appearing as G. aithos “thorn-bush” in the Gnomish Lexicon of the 1910s, a combination of G. aith “thorn” and G. tath “hedge”, derived from primitive ᴱ✶eχt·taþ· (GL/18). This word also appeared in Gnomish Lexicon Slips modifying that document (PE13/108).
Neo-Sindarin: I would adapt this word as ᴺS. eithos “thorn bush” for purposes of Neo-Sindarin, since the diphthong *ai* was *ei* in non-final syllables in Sindarin of the 1950s and 60s. I would re-etymologize this word as a combination of the later words [N.] êg “thorn” (< √EK) and [N.] toss “bush”, where primitive *ekt-* became *eith-*.