(philosophy) The argument that an omnipotent and truly benevolent deity would not permit evil.

(sciences) A simplified problem with clear constraints and parameters, usually used as a tool to understand a related real-world problem.

is there any problem?

(philosophy) A problem that arises solely as a result of a misuse of language

alcoholism

A mathematics question that states verbally what is usually expressed with symbols or diagrams.

plural of problem space

(social planning) A problem that is difficult or impossible to solve because of incomplete, contradictory, and changing requirements that are often difficult to recognize.

(idiomatic) A problem expected with any new and untried product, system, or venture

(mathematics) A mathematical problem, asking whether a room with mirrored walls can always be illuminated by a single-point light source, allowing for repeated reflection of light off the mirrored walls. It was solved in 1958: there are such rooms that cannot be thus illuminated.