plane figure
Noun
Meaning
a two-dimensional shape
Source: WordNetSynonyms
Hypernyms
Hyponyms
Examples
For example, consider the following genus-differentia definitions: * a triangle : A plane figure that has three straight bounding sides.
Those definitions can be expressed as a genus ("a plane figure" and two differentiae ("that has three straight bounding sides" and "that has four straight bounding sides", respectively).