Given a triangle Δ A B C and a point P not a vertex of Δ A B C, define the A'-vertex of the circumcevian triangle as the point other than A in which the line A P meets the circumcircle of Δ A B C, and similarly for B' and C'. Then Δ A' B' C' is called the circumcevian triangle of Δ A B C.

circum-medial triangle | circum-orthic triangle