Cynosure: the dog's tail, from the Greek kyon, kynos, dog, oura, tail.
Some time around 300 BC in his one surviving work, the Greek poet Aratus decided to name as "The Dog's Tail" that constellation we now know as Ursa Minor (previously called "the Dragon's Wing", and considered part of Draco).
Of course Ursa Minor includes Polaris (the North Star) among its attractions, and it is because of this that the word came to acquire its current meaning of anything that is the centre of attention, or that acts as a guide.
Meadows trim with daisies pied,
Shallow brooks, and rivers wide,
Towers, and battlements it sees
Bosomed high in tufted trees,
Where perhaps some beauty lies,
The cynosure of neighbouring eyes.
L'Allegro, John Milton (1645)