Scrabble Words of the Day -- COS+

Today's words play off of COS. You can easily hook off of COS with the following words:

COSH
COSS
COST
COSY

However, you can also add to the word with a mere 2 letters more, which you do to catch a triple-word score, for instance; or you might even extend the initial word COS when you're first playing it. Here are words you can build by adding just 2 tiles to COS:

COSEC
COSET
COSEY
COSIE
COSTA