Cup

From Brickipedia, the LEGO Wiki.

A cup is a item that Minifigures can hold in their hand. The are in various sets and are even used to look like headlights. They come in many color such as clear, brown, black and gold. They have also looked differently in each set such as in the Lego Castle where they look like wine cups. While in the older sets, you might find a cup that looks like a coffee mug.