L and I were recently talking about whether trilemma is a word. It seemed dubious since the dictionary.com only lists the entry from dictionary.com:

–noun
1. a situation, analogous to a dilemma, in which there are three almost equally undesirable alternatives: His trilemma consisted in not knowing whether to acknowledge receipt, deny it, or simply leave.
2. Logic. a form of argument in which three choices are presented, each of which is indicated to have consequences that may be unfavorable.

Furthermore, this seems very much in the modern style of extremifying words as the origin of new words. (This problem is so big, it’s not just a DIlemma, it’s a TRIlemma!)

But thinking about the fact that it’s a logic term, I’m pretty sure it’s a word. If a dilemma is a choice between two negative alternatives, then it makes sense that a choice between three negative alternatives would be a trilemma. A simple google search bears this out. The fact that it’s used in quotes suggests to me that it’s a technical term that’s moving into common parlance.