visual studio - Specific form of Constructor in C# -

I am reading ICT, one of my courses is C # and the other physics is our physics teacher, to make some movements animate Used Visual Studio, gave us some code which he did. They asked us to see it. Here is something that I do not recognize:

  public static vector operator + (vector v1, vector v2) {new vector return (v1.x + v2.x, v1.Y + v2. Y, V1.z + v2.z); }  

It is considered a constructor, but I have never seen anything like this before. I do not know what it's been told, so I do not know who is google for.

Can someone please me?

This is not constructor; What happens if you do something like: -

  var vector v1 = new vector (1,2,3); Vector vector v2 = new vector (1,2,3); Vector v3 = v1 + v2;