A noun for “lamp” appearing in The Lord of the Rings Appendix E (LotR/1121) as the name of tengwa #3 [a] (LotR/1122). In notes from the 1960s, Tolkien clarified that it was “a lamp or other device for shining light” (PE17/180).
Conceptual Development: In the Qenya Lexicon of the 1910s, ᴱQ. kalma was glossed “(day)light” under the early root ᴱ√KALA “shine golden” (QL/44) but was simply “light” in the contemporaneous Poetic and Mythological Words of Eldarissa (PME/44). It was glossed “light” again in the Early Qenya Grammar and English-Qenya Dictionary from the 1920s (PE14/43, 73; PE15/74). In the Earendel poem written around 1930 it was glossed “light” as in “light of the sun” (MC/216), but in the Oilima Markirya poem it was glossed “candle” (MC/214).
The word ᴹQ. kalma appeared unglossed in the Declension of Nouns from the early 1930s (PE21/52), but was glossed “a light, lamp” in The Etymologies from around 1937 under the root ᴹ√KAL “shine” (Ety/KAL), which is the first time it was used for “lamp”. It was glossed “light” in notes on The Feanorian Alphabet and Qenya Spelling from the 1930s and 40s (PE22/22, 51, 61), but became “lamp” in the discussion of tengwar in The Lord of the Rings itself, as noted above.
Meanwhile, the earliest “lamp” word was ᴱQ. kalumet (kalumett-) from the Qenya Lexicon and Poetic and Mythological Words of Eldarissa of the 1910s (QL/44; PME/44), and this word was mentioned again in the Early Noldorin Dictionary of the 1920s as a cognate to ᴱN. glavaith “a blaze, burning, blazing light” (PE13/162). ᴹQ. kalumet “lamp” appeared a final time in the Declension of Nouns from the early 1930s, but there it was deleted (PE21/37 note #134).
In summary, it seems that in the 1910s and 20s kalma was “light” while kalumet was “lamp”, but sometime in the 1930s kalumet was abandoned and kalma became “lamp, a [device for] light”, while in after the 1930s the ordinary word for “light” became cala (RGEO/62; Ety/KAL) which in the 1910s had instead been used for “daytime” as a time period (QL/44).
calma noun "lamp, a light, device for shining light" (Appendix E, KAL, PE17:123, 180), also name of tengwa #3 (cf. calmatéma), which was also already its name in the mostly pre-classical Tengwar system presupposed in the Etymologies(VT45:18, there spelt "kalma"). In early "Qenya", calma ("k") meant"daylight" _(LT1:254; in MC:213, the word is translated "light").Plural instrumental calmainen ("k") "lights-by", by lights (MC:216)_