Special Segments and Points in Triangles
Concurrent lines are lines that meet in a single point. Typically if we are refering to the point where two lines meet we called it a point of intersection. If more that two lines intersect at a single point we refer to that point as the point of concurrency. It is very common for two lines to intersect, but its is quite "special" for three or more lines to be concurrent. Often points of concurrency have special circumstances involving their creation.
Special Segments in a Triangle
Angle Bisectors & the Incenter
Perpendicular Bisectors of Sides & the Circumcenter