reflector

noun

1. Something which reflects heat, light or sound, especially something having a reflecting surface.

   “Then came a maid with hand-bag and shawls, and after her a tall young lady. She stood for a moment holding her skirt above the grimy steps,[…], and the light of the reflector fell full upon her.”

2. A reflecting telescope.
3. A small, often red, reflecting disk on the rear of a vehicle or bicycle that reflects the headlights of other vehicles.
4. A safety reflector.
5. One who reflects on something; one who thinks or considers at length.

   “Most reflectors on leadership are comfortable thinking of "ethical" and "unethical" as modifiers of leadership.”

   “Nonreflectors simply thought through that which they already knew, reflectors evaluated experiences by interpreting these experiences, and critical reflectors re-evaluated their presuppositions to correct distortions in reasoning and attitudes.”

6. Something that is reflective (indicative) of something else.

   “The biography is an enormously powerful reflector of mainstream values: it is a statement that this person is someone, or did something, worth writing about. Similarly, because the biographer has access to myriads of details about her or his subject, what gets full exposure and what gets swept under the carpet can be more indicative of the biographer's values (and the society that instilled them) than of the actual subject's life.”

7. A pattern which can change the direction and/or offset of an oncoming spaceship without being destroyed.