The meaning of Erastus is Lovely and  Beloved. Its origin is Variant of the Greek name Erastos. Erastus is a form of Erastos and is generally pronounced like eh RAS tus. This name is mostly being used as a boys name. Last year it ranked 4,160th in the U.S. Social Security Administration list of most popular baby boy names.
Which undefined term is needed to define an angle? Plane Point Ray Line. Undefined, you need a line to define an angle (if you're looking for undefined terms). This is because, if you think about it, a ray is part of a line.
Angle Bisectors in a Triangle. The definition of the angle bisector of a triangle is a line segment that bisects one of the vertex angles of a triangle. In general, an angle bisector is equidistant from the sides of the angle when measured along a segment perpendicular to the sides of the angle. Click on image for interactive Geometer's Sketchpad version.