In Tolkien’s later writing, this word mostly functions as a reduced form of Q. curwë “skill” used as an element in some Quenya names such as Q. Curufinwë and Q. Curumo.
Conceptual Development: In the Qenya Lexicon and Poetic and Mythological Words of Eldarissa of the 1910s ᴱQ. kuru was glossed “magic, wizardry”, and Tolkien further specified that it was used “of the good magic” (QL/49; PME/49). See S. curu for a discussion of the applicability of this word to “magic”.
sairina adj.? "magic" (evidently adj. rather than noun) (GL:72)