'Coplanar' definitions:

Definition of 'coplanar'

(from WordNet)
adjective
Lying in the same plane

Definition of 'Coplanar'

From: GCIDE
  • Coplanar \Co*plan"ar\ (k[-o]*pl[=a]n"[~e]r), a. [Pref. co- + plane.] (Math.) Situated in one plane. [1913 Webster]