A verb in the Gnomish Lexicon of the 1910s gloss “to bud” (GL/70), likely based on the early root ᴱ√TETE “bud, blossom” from the contemporaneous Qenya Lexicon (QL/92).
Gnomish
teth
noun. bud
tethil
feminine name. Tethil
tethlas
noun. petal, *(lit.) bud-leaf
tethla-
verb. to bud
tathrin
noun. willow
A noun appearing as G. tethlas “petal” in the Gnomish Lexicon of the 1910s, a combination of G. teth “bud” and G. lass “leaf” (GL/70), the latter sometimes also used for “petal” according to Tolkien’s notes in the 1910s (GL/52).
Neo-Sindarin: For purposes of Neo-Sindarin, I would adapt this word as ᴺS. tuilas “petal” using the 1930s word [N.] tui “bud” instead of 1910s teth. However, I would use S. lass only for “leaf”, not “petal”.