A noun in The Etymologies of the 1930s glossed “hound” derived from primitive ᴹ✶khugan under the root ᴹ√KHUG “bark, bay” (Ety/KHUGAN). It was followed a parenthetical form (húnen), likely a genitive, indicating a stem form of hún-. This word served as the basis for the name of the great Valinorian hound Huan.
Conceptual Development: The forms huan and {hwan >>} huan appeared in both the Qenya Lexicon and Qenya Phonology of the 1910s, but in both cases this word was revised to ᴱQ. fan (fand-) “dog” (QL/37; PE12/26). This word was derived from the early root ᴱ√SAẆA < sǝwǝ (QL/82) and primitive forms ᴱ✶swandǝ (PE12/26) or ᴱ✶swǝnd- (QL/82). The vacillation from huan to fan reflects Tolkien’s uncertainty on the development of initial sw- in Early Qenya, either to hw- > hu- or to f- (PE12/26 note #26). The form ᴱQ. huan (huand-) “dog” appeared in Early Qenya Word-lists of the 1920s (PE16/132). It appeared again in The Etymologies, with a new gloss “hound”, a revised derivation and a new stem form hún- (see above).
A word in the Declension of Nouns from the early 1930s with stem form hun- and gloss “earth” (QL/39). It might be a later iteration of ᴱQ. han “ground, earth” from the Qenya Lexicon of the 1910s (QL/39), and if so then hún might also be used as “✱ground”. I think it is useful to assume so for purposes of Neo-Quenya, as the other attested word for “ground”, Q. talan, is probably used more often for “floor”, including floors above the ground level.