Adjacent sides.
They are co-terminal angles.
If I understand your question, you are referring to the vertex. This is the point where the sides meet, also where the angle is formed.
A point, line or curve.
The call to holiness that all Christians share is our common vocation.
vertex
Adjacent angles.
I would call him by his name. You do not share a common ancestor, so are not related.
They would be intersecting.
The vertex (or apex).
Give both sides of the argument
In most cases you would call him by his name. You do not share a common ancestor, so aren't really related.
They are called "linguistic or language communities."