Middle Primitive Elvish
rim
root. abound; large number
kol
root. round, (?rim)
ringi
root. cold
lai-
prefix. *many
lin
root. pool
lī
noun. number
There are more words but they are from Tolkien's earlier conceptional periods. Tolkien likely changed these words as he evolved the aesthetics and completeness of the languages. You may even find languages that Tolkien later rejected. Do not mix words from different time periods unless you are familiar with the phonetic developments.
Below: Tolkien's Late Period (1950–1973). These are from Tolkien's late conceptual period — his most settled forms of the languages. Prefer these over the earlier ones above when composing new text.
A likely precursor to this root appeared in the Qenya Lexicon of the 1910s as ᴱ√‘(A)ṚM(A)R and ᴱ√‘ṚMṚ with a Gnomish form ᴱ√grimri· (QL/32), indicating the actual primitive form was ✱ᴱ√ƷṚMṚ. Derivatives of this early root include ᴱQ. arm- “gather, collect” and G. grim “host, folk”, the last of these the likely precursor to N. rhim.
The root ᴹ√RIM appeared in Primitive Quendian Structure: Final Consonants from 1936, glossed “host, large number” >> “number, plenty” (PE21/57). It also appeared in The Etymologies written around 1937, with gloss “abound” and derivatives such as ᴹQ. rimbe/N. rhim “crowd, host” (Ety/RIM). The roots ᴹ√SRĪ, SRĬMĬ, and SRIMBI “abound” appeared in Demonstrative, Relative, and Correlative Stems (DRC) from the late 1940s, quickly revised to ᴹ√RĪ, RĬMĬ, and RIMBI (PE23/100 note #34). Quenya and Sindarin forms Q. rimbë and S. rim continued to appear in Tolkien’s later writing (Let/382; PE17/50; UT/318), so it is likely the root √RIM remained valid, especially given the prevalence of suffix -rim in Sindarin collective names.