A noun appearing as G. tadhos “hawthorn” in the Gnomish Lexicon of the 1910s, an elaboration of G. tath (tadh-) “hedge” based on the early root ᴱ√tadh- (GL/68).

Neo-Sindarin: I would retain ᴺS. tadhos “hawthorn” based on an updated Neo-Root ᴺ√TAD “enclosure”; see that entry for details.