Quenya noun for a “deed”, a combination of the verb car- “to do” and the verbal suffix -da used for the product of an action (PE17/51; PE22/152), thus literally “✱a thing done”.
Conceptual Development: Perhaps the earliest precursor of this word is ᴱQ. karma “shape, fashion; act, deed” in the Qenya Lexicon from the 1910s of similar derivation (QL/45). In The Etymologies from the 1930s, the word appeared as ᴹQ. kar (kard-), but this gloss was rejected and replaced by ᴹQ. kar “building” (Ety/KAR). The form karma “deed” also appeared in some later writings, but was rejected (PE22/138).
-da suffix used to derive nouns denoting the result of an action, like yulda "draught, the amount drunk" (the stem YUL is here given the meaning "drink"). (PE17:68) Cf. also carda "deed" (q.v.) vs. the verb car- "do".