[uoaei]

The "trivia" tests, when used (IMO) correctly, are not for testing whether or not the candidate recognizes the term and can regurgitate a definition. I prefer to listen to how they phrase their response to get a sense of the intuition behind the understanding of the concept as well as how it may fit in to a larger mathematical framework (i.e. their internal model for mathematical analysis).

I am not looking for someone to answer the question correctly, but to answer the question in a way that demonstrates deeper insights, which helps immensely in research settings as re-using properties of mathematical constructs in novel ways is often how theory and practice both are advanced.

I would be much less interested in someone giving a precise definition of eigenvalues than to describe them in such a way that they understand e.g. what can be deduced about an operator when one of its eigenvalues is zero.