The Outsider definitions

These definitions and explanations come from Bill, one of my very good friends. He did the research. See The Tower.
sere
(especially of vegetation) dry or withered
nonce (for the nonce)
1) the one or present occasion, purpose, or use
2) the time being
eidolon
In ancient Greek literature, an eidolon is a spirit-image of a living or dead person, a shade or phantom look-alike of the human form.
nepenthe
Nepenthe is a possible fictional medicine for sorrow – a "drug of forgetfulness" mentioned in ancient Greek literature and Greek mythology, depicted as originating in Egypt. (Poe speaks of this drug.)
Neb
This might be a word Lovecraft invented.
Nephren-Ka
Nephren-Ka, "The Black Pharaoh" (also called Nophru-Ka), is a fictional pharaoh of Ancient Egypt invented by Lovecraft, who depicted him as a worshipper of the Outer God Nyarlathotep. Later versions of the Cthulhu Mythos presented him as an avatar of Nyarlathotep himself.
Nitokris
Nitocris (Greek: Νίτωκρις) was possibly the last queen of the Sixth Dynasty of Ancient Egypt. Her name is found in writings long considered as relatively accurate resources: a major chronological documentation of the reigns of the kings of ancient Egypt that was composed in the third-century BC by Manetho, an Ancient Egyptian priest, and by the ancient Greek historian, Herodotus, in his Histories (430 BC). She is thought to be the daughter of Pepi II and Neith and to be the sister of Merenre Nemtyemsaf II.

Bill provided another source for Lovecraft stories:
​https://archive.org/details/hplovecraftcompleteworks/HP-Lovecraft-Complete-Works-Vol-I/mode/1up?view=theater​