Definition of bisect

In geometry, to bisect is to divide a geometric figure such as a line, an angle or any other shape into two congruent parts (or two parts that have the same shape and size).

You could bisect a segment with a point

Since point A divides the segment into two parts that have the same size and shape, the segment is bisected.

You could bisect an angle with a ray

Since ray AB divides the angle into two parts that have the same size and shape, the angle is bisected.