Reflection, as used in psychology, refers to the therapist’s “reflecting” back the client’s words (reading or saying the client’s words back to the client). This is done to allow the client to hear for themselves what they have said and evaluate the logic or reasoning behind their own statements.
For instance, people often accept things that they have been told since childhood as truth–but when they hear it reflected back to them, they can see the illogic or unfairness of something that they have always accepted as a fact., i.e. being told by a parent “you’re ugly or stupid or worthless” and having let that define their self-image as an adult.