A word in The Etymologies of the 1930s glossed “white fog, wet mist” derived from the root ᴹ√MITH (Ety/MITH). As a later addition to this entry, Tolkien instead gave N. mith “grey”, and that was how this word was typically used in Tolkien’s later writings.
Noldorin
hithw
noun. fog
hithw
noun. fog
mith
noun. white fog, wet mist
hith
noun. mist, fog
mith
noun. white fog, wet mist
hîth
noun. mist
daw
noun. night-time, gloom
doll
adjective. dark, dusky, obscure
dolt
adjective. dark, dusky, obscure
dûr
adjective. dark, sombre
dûr
adjective. dark
fuin
noun. night, dead of night, gloom, darkness
tindu
noun. dusk, twilight, early night (without Moon)
tindu
noun. starry twilight
tinnu
noun. dusk, twilight, early night (without Moon)
tinnu
noun. starry twilight
A noun in The Etymologies of the 1930s given as N. {heðw >>} hithw “fog” derived from primitive ᴹ✶khithme under the root ᴹ√KHITH “mist, fog” (Ety/KHIS; EtyAC/KHIS).
Conceptual Development: G. huith “fog” from the Gnomish Lexicon of the 1910s is a likely precursor (GL/49), perhaps derived from a (hypothetical) early root ✱ᴱ√HUYU.
Neo-Sindarin: If adapted to Neo-Sindarin, this word would become ᴺS. hithu, as suggested in HSD (HSD).