This is a Coffee Hottle -- a "hot bottle," or hottle of thick glass to hold your hot coffee in a restaurant.

It's essentially a personal restaurant carafe for your hot coffee when you ordered coffee -- and these were often served atop a cup, so the bottom of the carafe "locked into" the cup and they'd be carried as a unit.

This example is by Glasbake and it is in excellent condition. It stands approximately 5 1/2 inches tall and is approximately 1 7/8 inches in diameter at the top. It has no cracks or chips whatsoever.