The Quenya word for “feather” and the name of tengwa #4 [z] (LotR/1122).
Conceptual Development: Some similar words appeared in the Qenya Lexicon of the 1910s under the early root ᴱ√QASA: ᴱQ. qasil “arrow-feather, arrow” and ᴱQ. qasilla “tuft, nodding spray, tassel, plume” (QL/76); quasil was only glossed “arrow” in the contemporaneous Poetic and Mythological Words of Eldarissa (PME/76). ᴹQ. qesse “feather” first appeared in The Etymologies of the 1930s under the root ᴹ√KWES (Ety/KWES), already the name of tengwa #4 (EtyAC/KWES). It was also the name of this tengwa in notes on the Feanorian Alphabet from the 1930s and 1940s (PE22/22, 51, 61), and remained so into the published version of The Lord of the Rings.
quessë noun "feather", also name of tengwa #4 (Appendix E, WJ:417, KWES, VT45:24); súriquessë "wind feather" (referring to a "tuft of radiating grass" in a drawing by Tolkien) (J.R.R. Tolkien: Artist & Illustrator, p. 197)