Q. 1. What is the purpose of the pyx?

A. 1. A pyx or pix (Latin: pyxis, transliteration of Greek, boxwood receptacle, from box tree), is a small round container used in the Catholic Churches to carry the Consecrated Host (Eucharist), to the sick or those otherwise unable to come to a church in order to receive Holy Communion.

The plural of pyx is pyxides. While the word may be applied to any covered carrier, in the modern usage the term is usually applied to a small, flat, clamshell-style container often about the size of a pocket watch and usually made of brass or other metals, traditionally lined with gold. A fabric or leather pouch in which the pyx may be carried is known as a burse. Typically, this kind of burse can be securely closed and is fixed with cords so that the priest, deacon, or Extraordinary Minister of Holy Communion can affix it to his or her person during transport to prevent the Consecrated Host(s) from being accidentally lost.

[Source: https://en.wikipedia.org/wiki/Pyx]