Employment Law Questions? Ask an Employment Lawyer.
I guess it is a matter of semantics. Discharged technically includes both termination for cause (getting fired) and termination for convenience (getting laid off). So you can probably safely answer either way.
But your potential employer may have a different definition than you, so full disclosure is the safest route. Just put "I have never been terminated for cause or forced to resign" and you will be covered regardless of their interpretation. Or even state that you were laid off for economic reasons.