It's two syllables (the final e is pronounced).

I've always pronounced it with the e's long--kee thee--but sitting here thinking about it this morning, I am suddenly suspicious that I may be wrong, and it's actually keh theh, which is how it's pronounced as part of the name of Phi-Kethetin.

So, um. I'm sure about the two syllables, but other than that apparently scholars disagree. :)