anca noun "jaws, row of teeth" _(ÁNAK [there spelt anca in Etym as printed in LR, but according to VT45:5, Tolkien's own spelling in the Etym manuscript was anka], NAK [there spelt anka], Appendix E, SA - despite what Christopher Tolkien says in the entry _anca in SA, the Quenya word anca_ as such does NOT appear in the Sindarin dragon-name Ancalagon, but its Sindarin cognate anc does. See ÁNAK in the Etymologies.) Also name of tengwa #15 (Appendix E). _Despite its English gloss, anca is a singular word (in Etym the gloss is indeed "jaw", not "jaws").
Quenya
anca
noun. jaws, jaws; [ᴹQ.] jaw, row of teeth
anca
jaws, row of teeth
anca
noun. jaws
jaws, (animal's) mouth
A noun for “jaws” appearing in The Lord of the Rings Appendix E as the name of tengwa #15 [f] (LotR/1123). ᴹQ. anka was first introduced in The Etymologies of the 1930s with the glosses “jaw, row of teeth” and derived from primitive ᴹ✶ankā under the root ᴹ√(A)NAK “bite” (Ety/ÁNAK, NAK).
Conceptual Development: In tengwar charts and other earlier documents from the 1930s up through the early 1950s, anca was in competition with an earlier word anta “jaw” < ✶amtā (earlier ᴱ✶ṃtā) based on the root √MAT “eat” (PE22/22, 51; PE18/85 note #72), but Tolkien ultimately settled on anca. Another early word that might be a precursor to anca is ᴱQ. kâ, cognate to G. gag “jaw” from the Gnomish Lexicon of the 1910s (GL/37).