planar
/ˈpleɪnɑr/Definitions
1. adjective
relating to or having a flat or two-dimensional surface
“The planar design of the city’s architecture made it easy to navigate.”
2. noun
a plane in geometry
“The planar surface of the paper was a perfect example of a plane in geometry.”
3. noun
a geometric figure or configuration that lies in a plane
“The mathematician studied the properties of a planar graph.”