Kappa is derived from the Semitic 'kap', which means 'open hand' - because their word for hand started with that sound. So perhaps 'clap' now makes sense, as the sound the hand makes. Kind of neat.
Don't forget to grab the editable eps and use the character for your project, or smash it up and send me a copy back. The edit's I'll feature here as a changelog to track its development.