kapak

1. eyelid
   Kapci su mi teški, idem da spavam. — My eyelids are heavy, I'm off to bed.
   Stavila je senku na kapke. — She put eyeshadow on her eyelids.
2. (on a window) shutter
   Zatvori kapke, sunce previše udara. — Close the shutters, the sun is too strong.
3. lid; flap
   Podigao je kapak klavira i počeo da svira. — He lifted the piano lid and started to play.

For the lid of a pot or jar, poklopac is the usual word.