cat's eye

Short definition from Wiktionary

Noun

1. 1
   A retroreflective device placed on a road surface as a marking that can be seen even at night.
2. 2
   A glass marble with elongated colourful inclusions running through its axis.
3. 3
   A gemstone exhibiting chatoyancy.
4. 4
   Cymophane (translucent yellow chatoyant chrysoberyl).
5. 5
   A sea snail, Lunella smaragda
6. 6
   Used other than figuratively or idiomatically: see cat, eye.; the eye of a cat.
7. 7
   Alternative form of cat's eye.