os

noun

1. 1

   the left eye

2. 2

   a hard brittle blue-grey or blue-black metallic element that is one of the platinum metals; the heaviest metal known

3. 3

   rigid connective tissue that makes up the skeleton of vertebrates

4. 4

   (computer science) software that controls the execution of computer programs and may provide various services

5. 5

   a mouth or mouthlike opening