Final answer:
The midway point is used as a negative reference point that helps define positive and negative directions in relation to other positions or limbs.
Step-by-step explanation:
In the context of this question, the term 'midway point' refers to the middle point between two other limbs or positions. It is used as a negative reference point to define the positive and negative directions. For example, if we consider the distance from Kosma's house to the school as -300 m, and we choose the school as the negative reference point, then the distance from Kosma's house to the shop (in the opposite direction) would be +300 m, using the shop as the positive reference point.