Several students asked about this. If you answer the question in a way
that a freshman undergraduate understands, I.e., you do not use any
terms with specialized meanings, you will need to mention certain
procedures.
Terms like "reducible" and "nondterministic" will require additional
explanation for an uninitiated audience.
In the texts, they spend pages building up the terminology. When they
finally give the definition, it is pretty meaningless by itself.
You need to know all the prior definitions.
The idea of this question, "in your own words" is that you explain
these concepts in commonly known terminology. That way, you have
a chance that you'll actually remember it and use it someday.
--Allen