A variant of Elendil appearing in The Etymologies from the 1930s (Ety/SER), perhaps a compound of the root ᴹ√ELED “star-folk, Elf” and the suffix -ser “friend”, as indicated by the archaic form †Eleðser.
Qenya
elendil
masculine name. Elf-friend
elendilion
proper name. Descendant of Elendil
elendilli
collective name. Elf-friends
elesser
masculine name. Elf-friend
Apparently a name for the kings of Gondor as descendants of Elendil in Lord of the Rings drafts from the 1940s, appearing in its Anglicanized plural “Elendilions” (WR/76). It is a compound of the name Elendil and the patronymic suffix -ion.