The Litron cup, also known as the "square cup", derives its name from the Latin word "libra", which expressed a unit of liquid measurement. Its precise size is not consistent, however, as four variations with different measurements exist. The shape of the saucer, which always accompanied the cup, is noteworthy for its raised sides and deep well.

The litron cup was first seen at the Vincennes factory in 1752, when the consumption of hot chocolate, tea and coffee began to grow in popularity. As the shape of a tea cup evolved to be a different shape from that of a coffee cup, the litron shape became strictly associated with the consumption of coffee. Interestingly, until the beginning of the XXth century, it was quite acceptable etiquette to pour a small amount of hot coffee from a litron cup into its saucer to cool coffee before drinking. The litron cup is almost always a separate collection from a dinnerware service: it is a unique object, decorated with many original designs on a timeless shape. Thus, the litron cup represents the changing styles from different eras and this unique characteristic renders the historical cups and saucers collection from the Ancienne Manufacture Royale even more collectible.