I live where waves and whispers meet, With hinged-up doors instead of feet. I shut my mouth when danger’s near, Yet sometimes hold a treasure dear.

The first part of me is used in many phrases, like keep an me on it, seeing me to me, or turn a blind me. The second part is something cats knock off the table, or what makes the clear part of a window. Put them snugly together, and make it plural, and you have something that slides down your nose if ill fitted.

Teach a someone to use this and you'll feed them for a lifetime. Use it from a boat, a pier or any place related to maritime. A little bait and you'll reel Until a tug, a bite you feel.

I can be a dose of medicine, or a slab of stone, or something you use to watch Netflix. What am I?

I need four to be a utensil, While three rule the sea. Different counts of prongs Help to name me.