The word Pyx is rooted in Greek and means a container. The full word it originates from is Pyxis. Additionally the pyx is carried in a fabric pouch which is called a burse. This is the proper way to transport the Pxy. The Eastern Catholic church view the pyx as a .portable. tabernacle that is used to hold a host. In the Roman Catholic church the pyx is also known as a lunette.

A lunette, a German term that means a crescent shaped item that is made of gold or silver that is made to hold a host upright in an item such as a monstrance. The host is set in the lunette or stand to provide a secure stand to hold the host in. In the actual Monstrance, there is a pyx that is made of glass. This was set this way so that the Precious Body, or consecrated host, would not touch the glass of the Monstrance. There is a slot in the Pyx that the Lunette slides into the Monstrance that helped insure that the Host does not tip or lean. The Lunette was used largely before the period of Reformation and it part of many antique monstrances that predate the 15th century.

The pyx is also used often by missionaries, this is in addition to those who use one to carry Eucharist to people who cannot attend mass within a particular community. The Missionary may use a pyx to carry the Eucharist into a mission type area. The pyx is filled with Eucharist, or consecrated host. They used a the Eucharist and a and a breviary, or set of prayers to hold large communion services which Eucharist is offered to large groups of people.

Through the centuries the pyx has been made of different materials and are constantly being redesigned to better serve the user. In the modern era, most are shaped like a pocket watch with an ornate image of something to do with Jesus, the Eucharist. Many bare the image of a Challis, which is used to distribute the Precious Blood. Some are designed with the Lamb of God on them, which is common image to represent Jesus, the Lamb of God or our Pascal Sacrifice. There are some with wheat and grain imagery on them, symbolized the bread of life that comes from grain. These are all universal symbols for Eucharist and why they are ornately displayed as part of the pyx.

Antique Pyxides, the plural of the word pyx, were also made of glass or carved from wood. Some were very ornate and Large, almost more like a modern day tabernacle, these can hold many hosts making it easier for larger distributions. Oppositely some are very small and palm-sized which service only one or two communicants.

Whether the 15th century or the 21st century, the pyx is a is used in the exact same manner though out the world and throughout time.