Cynosure (3 syl.). The polar star; the observed of all observers. Greek for dog's tail, and applied to the
constellation called Ursa Minor. As seamen guide their ships by the north star, and observe it well, the
word "cynosure" is used for whatever attracts attention, as "The cynosure of neighbouring eyes" (Milton)

I learned "cynosure" in highschool, but never saw the etymology before.