Euler line

noun2

1. •
   A line that, for a given triangle, passes through several important points, including the circumcentre, orthocentre and centroid; an analogous line for certain other 2- and 3-dimensional geometric figures.

   • Since the line joining the circumcenter and orthocenter of a triangle is its Euler line, we see that this parabola is the envelope of the Euler lines of the triangles Aᵢ. — 1983
2. •
   An Eulerian path, a looped path through a graph that passes along every edge exactly once.

   • Theorem 2.1 A connected graph with even local degrees has an Euler line. — 1961