The white tree of Númenor (LotR/971, S/59), translated “White Blossom” (SI/Nimloth) or “Pale Blossom” (MR/155). It was also the name of the mother of Elwing, wife of Dior (S/234). This name is a combination of nim “white” and loth “flower” (SA/nim, loth).
Conceptual Development: In Silmarillion drafts from the 1930s, N. Nimloth “Pale Blossom” appeared as a Noldorin name for Silpion (LR/210), and in The Etymologies had essentially the same derivation as given above (Ety/LOT(H)).
nimp (“pale, white”) + loth (“a head of small flowers”)