A word for “maiden” or “✱young woman”, frequently appearing as suffixal -wen as an element in female names, derived from the root √WEN(ED) (PE17/191; Ety/WEN).
Conceptual Development: In the Gnomish Lexicon of the 1910s, the word G. gwin meant “woman, female” and G. {gwen >>} gwennin was “girl” (GL/45). The former was derived from the root ᴱ√giu̯i which had to do with pregnancy, but the latter was derived from {ᴱ√gw̯ene >>} ᴱ√gu̯eđe. In the contemporaneous Qenya Lexicon {ᴱ√WENE >>} ᴱ√GWENE was the basis of words like ᴱQ. ’wen(di) “maiden” (QL/103). In the Gnomish Lexicon Slips it seems G. gwin was also reassigned to the root ᴱ√(G)WENE [ᴱ√u̯enĭ-], derived from ᴱ✶u̯einā́, though possibly shifted or blended in meaning with an adjectival sense “womanly” (PE13/113).
In the Early Noldorin Grammar of the 1920s, Tolkien had ᴱN. uin “woman” (PE13/123), a form that also appeared with this gloss in contemporaneous Early Noldorin Word-lists as a replacement for deleted {gwind, gwinn} (PE13/146, 155). In The Etymologies of the 1930s, Tolkien had N. gwend, gwenn “maiden” under the root ᴹ√WEN(ED) which he said was “often found in feminine names” (Ety/WEN). He noted that “since the [suffixed names] show no -d even in archaic spelling, they probably contain a form wen-”. Tolkien seems to have stuck with these forms thereafter.
Neo-Sindarin: For purposes of Neo-Sindarin, I would use this word for a young woman or adolescent girl, especially prior to marriage, but for female children I would use neth.
_n. _maiden. Q. wendē. >> gwen, gweneth