A word for “all” appearing only in its mutated plural form phain in the King’s Letter from the phrase ar e aníra ennas suilannad mhellyn în phain “and he desires to greet there all his friends” (SD/129). It is almost certainly based on the root √KWA “complete, full”.

Neo-Sindarin: In a conversation on Vinyë Lambengolmor Discord Server (VLDS) from 2022-03-10 involving Arael, Raccoon, Lokyt, and Röandil it was suggested that pân might also mean “*complete, entire, full, the whole”. For purposes of Neo-Sindarin, I would use this word as both an adjective and a (pro)noun as in anno annin bân “give me [it] all”. As an adjective it would usually be in the plural: edhil bain “all elves” or i edhil bain “all [of] the elves”, except perhaps when modifying a mass noun: nen bân “all water” or i nen bân “all [of] the water”.

Also recall that Sindarin has a system of class plurals which are used to designate an entire class or all of a group in a given context, such as edhelrim meaning either “all of elvenkind” or “all the elves in this context”. Thus I would only use pân with an ordinary plural when it is necessary to emphasize the completeness or wholeness of the group in question. When used with a class plural I would give pân the sense “entire” or “the whole”. Compare Aran Edhelrim “King of Elvenkind” vs Aran Edhelrim Bân “King of the Whole of Elvenkind” (no elf excluded).