Problem

1. A question proposed for solution; a matter stated for examination or proof; hence, a matter difficult of solution or settlement; a doubtful case; a question involving doubt.
2. (Math.) Anything which is required to be done; as, in geometry, to bisect a line, to draw a perpendicular; or, in algebra, to find an unknown quantity.
Plane problem (Geom.),
a problem that can be solved by the use of the rule and compass.
Solid problem (Geom.),
a problem requiring in its geometric solution the use of a conic section or higher curve.