pyx also pix 
(pĭks)
(pĭks)n.
1. Ecclesiastical
a. A container in which wafers for the Eucharist are kept.
b. A container in which the Eucharist is carried to the sick.
2. A chest in a mint in which specimen coins are placed to await assay.
[Middle English pyxe, from Latin pyxis, box, from Greek puxis.]