cleft-peaks; criss (“cleft”) + aeg (S aegas “mountain peak, thorn”) + rim (collective plural suffix) [HKF] ss at the end of monosyllables is retained in intervocalic position.
crissaegrimplace name. *Cleft Mountain Peaks
Mountains south of Gondolin (S/121). The meaning of this name is unclear, but it may be a combination of criss “cleft” and aeg “point” with the class-plural suffix -rim. The second half of the word aegrim may have the same meaning as aeglir “range of mountain peaks”.
Conceptual Development: In Silmarillion drafts from the 1930s, this name first appeared as Dan. Gochressiel (LR/285). This name was designated Danian in The Etymologies, containing Dan. hrassa “precipice” and described as “a sheer mountain wall” (Ety/KHARÁS). The name was later changed to N. Crisaegrim with one s (LR/301). A second s was added in Silmarillion revisions from the 1950s-60s (WJ/193-4).
* CrissaegrimCleft Mountain Peaks
Crissaegrim is a Sindarin name meaning "Cleft Mountain Peaks", but it is usually referred to as the "Eagles' Cleft" or "Abode of Eagles".