Definition of coplanarity in US English:

coplanarity

noun

Geometry
  • See coplanar

    • ‘The desired condition is called coplanarity.’
    • ‘Quantum mechanical calculations suggest that internal rotation, which distorts the coplanarity of both rings of the molecule, increases the nonradiative decay rate of the excited chromophore.’

Pronunciation

coplanarity

/ˌkōˌplāˈne(ə)ritē/