The Sindarin word for “ten” in notes on numbers from the late 1960s (VT42/25; VT48/6). Its primitive form is ✶kwayam based on the root √kwaya originally referring to the whole (√KWA) set of ten fingers (VT42/24). In one place it had a longer variant pae(an) (VT48/21), which appeared in reduced form in the adjective paenui “tenth” (VT42/25).
Conceptual Development: The Gnomish Grammar of the 1910s had G. sath “10” of unclear derivation (GG/13). The Etymologies of the 1930s had N. caer “ten” derived from a variant √KAYAR of the root ᴹ√KAYAN “ten” (Ety/KAYAN), where the -r was borrowed from neder “nine” (EtyAC/KAYAN). In notes probably from the late 1950s Tolkien had caen- or cae “ten” (PE17/95), a form Tolkien probably used for some time given nelchaenen “thirtieth” from around 1950 (SD/129) and caenui “tenth” from the late 1960s (VT42/10), a rejected form of paenui appearing in the same 1960s notes on numbers mentioned above.
A Noldorin noun derived from ᴹ√KAY “to lie” mentioned in the Quenya Verbal System (QVS) from 1948 that was “used of a flat isle in a river, opp[osite] of toll-” (PE22/126). The same form caer appeared as a derivative of √KAYA in notes on Words, Phrases and Passages from the Lord of the Rings (WPP) from the late 1950s or early 1960s, but there it was unglossed and its meaning is unclear (PE17/101).