A word appearing as an element in the names S. Talath Dirnen “Guarded Plain” (S/168) and S. Talath Rhúnen “East Vale” (S/124). Christopher Tolkien gave this word the glosses “flat lands, plain” in The Silmarillion appendix (SA/talath).

Possible Etymology: This word was probably connected to the root √TAL “foot” in some way, which had other elaborations referring to flatness, such as √TALAM “a flat space” (PE17/52). Perhaps it was based on *√TALATH. In notes from 1964 (PE17/150; see below) Tolkien also considered giving the root √TALAT the sense “ground (bottom)”, so primitive *talatte is another possibility, though elsewhere √TALAT was usually a triconsonantal root unrelated to √TAL.

Conceptual Development: In earlier writings, this word was dalath. The first appearance of this earlier word was as ᴱN. dalath “vale” in the ᴱN. Nebrachar poem from around 1930 (MC/217). It appeared as N. dalath “flat surface, plane, plain” in The Etymologies of the 1930s as a derivative of the root ᴹ√DAL “flat” (Ety/DAL). In the contemporaneous Silmarillion drafts the name “Guarded Plain” appeared as N. Dalath Dirnen (LR/299). In Silmarillion drafts from the 1950s and 60s, this name was revised to S. Talath Dirnen (WJ/140).

Tolkien was vacillating on this issue as late as 1964, where in some etymological notes on the name Daleth Dirnen (DD) he first wrote: “DAL-, bottom, ground, (in Quenya > LAD-). Alter dalath to dalad, low lying / flat ground” but then above this wrote “X Dalath Dirnen. dalath won’t do = ‘plain’. {alter to talad. no that = slip, fall} TALAT = ground (bottom). hence TALAT- fall down” (PE17/150). Here he seems to have rejected dalath, but did not quite finish the transformation to talath, first considering talad as an alternative but rejected it because should mean “slip, fall” instead. He eventually settled on talath though, as indicated by the Silmarillion revisions mentioned above.