
A glass and plastic item that was found in a box of dishes:

"It's the top of a pitcher."
"It's an ice core for a pitcher. You fill it with water and freeze it. Fill your pitcher with the desired beverage and pop this in. Keeps drinks cold on the counter for long periods without diluting them. I have a couple and primarily use them for juices during holidays for my family brunch buffet. You can see the gap for pouring in the rim (you're holding it upside down)."