kappa

Etymology 1

Learned borrowing from Ancient Greek κάππα (káppa), ultimately from Proto-Semitic *kapp- (“palm, hand”). Doublet of kaph.

noun

1. The tenth letter of the Greek alphabet.
2. (finance) A measurement of the sensitivity of the value of an option to changes in the implied volatility of the price of the underlying asset.

Etymology 2

From Japanese 河童 (kappa, “water imp”).

noun

1. (Japanese mythology) A tortoise-like demon or imp.
   It was not quite possible for a kappa to go pale, but this one managed, shrinking partly into its shell. 2013, Laura VanArendonk Baugh, Kitsune-Mochi: Kitsune Tales #2, page 94