a jar or vase with a large oval body, narrow cylindrical neck, and two handles that rise almost to the level of the mouth; broadly : such a jar or vase used elsewhere in the ancient world
taken by Ricardo André Frantz, CC BY-SA 3.0
So, this one’s simply a term for items that you see less in modern life but would potentially be seen more in rpgs. You’ll see them on ships for transport, you’ll see them in ruins and tombs. As a GM use the term to draw attention to or away from loot or surroundings.