A word appearing in Definitive Linguistic Notes (DLN) from 1959 as tewch with an unclear gloss, perhaps “chip” as suggested by Christopher Gilson (PE17/148). It was derived from primitive ✶teswā where the sw became χw, and then the final w became u/w̯ which then intruded into the main syllable in a process parallel to i-intrusion.

Neo-Sindarin: This 1959 note it is the only place Tolkien mentions u-intrusion as a parallel to i-intrusion, so I assume this was a transient idea and the Sindarin form should be ᴺS. techu “chip”.

Conceptual Development: The Gnomish Lexicon of the 1910s had G. flinc “chip” (GL/35), probably based on the early root ᴱ√FḶKḶ “cleave, hew” (QL/38).