The term cabochon comes from a French word that means head.  Cabochon is often abbreviated as cab.  A cabochon is a gemstone that has been cut into a shape then polished.  Opaque stones are usually made into cabochons while transparent stones are faceted.  

Asteriated stones are gems that have a star reflection, such as a star sapphire.  The star would not be visible in a faceted cut, but is shown off brilliantly in a cabochon.