LESSON 2: Subsets of a Line Definition P Q The segment with endpoints P and Q, denoted by PQ, is the set consisting of distinct points P and Q and all points in between P and Q. Р Q R Ray PQ is the set of points consisting of PQ and all points R such that Q is between P and R. P is called the endpoint of the ray. The symbol PQ is used to name ray PQ. Example 3: Terms Related to Lines Point E is between Q and D. Which of the following is true? Q, E, and D are collinear. a. b. QD and DQ are the same. C. EQ is the same as ED. 8.​