A word for “bride” in The Etymologies of the 1930s derived from primitive ᴹ✶ndīse under the root ᴹ√NDIS (Ety/NDIS). Ordinarily the s in this word would have been lost, but it was influenced by N. †dess “young woman” < ON. ndissa from the same root (EtyAC/NDIS). Dîs “bride” in turn influenced the form of N. †dî “woman”, originally ON. nī < ᴹ√NĪ (Ety/DER, NĪ¹; EtyAC/NDIS).
Neo-Sindarin: While I think this word is perfectly serviceable, for purposes of Neo-Sindarin it may be better to use the longer and more distinctive word dineth for bride.
A noun in The Etymologies of the 1930s for “woman” derived from the root ᴹ√NĪ of the same meaning (Ety/NĪ¹). It began with d- due to the influence of N. dîr and as partial blending with derivatives of ᴹ✶ndisi “bride” (Ety/DER); its Old Noldorin form was ON. nī (Ety/NĪ¹). In The Etymologies, this word was archaic: “dî was only rare and poetical (‘bride, lady’): it was replaced in sense ‘woman’ by bess [see BES], and in sense ‘bride’ by cpd. di-neth” (Ety/NĪ¹). The scenario in The Etymologies was that the word N. bess itself originally meant “†wife” but came to mean “woman”, much like its male counterpart N. benn meant “†husband” came to mean “man” (Ety/BES).
Conceptual Development: Earlier words of similar form include (archaic) G. †nîr “woman” from the Gnomish Lexicon of the 1910s (GL/60) and (rejected) ᴱN. {nain} “woman” from the Early Noldorin Grammar of the 1920s.
Neo-Sindarin: The word S. bess reappeared in later writings with the gloss “wife” (SD/129), indicating Tolkien probably abandoned the scenario in The Etymologies whereby dî became archaic and was replaced by bess for “woman”. As such some Neo-Sindarin writers restore ᴺS. dî as the word for “woman”; this was first suggested to me by Elaran and it is my current recommendation. However, N. bess remains popular for “woman” in Neo-Sindarin as well.