Pix
WordNet
noun
(1) Any receptacle in which wafers for the Eucharist are kept
(2) A chest in which coins from the mint are held to await assay
WiktionaryText
Etymology 1
First attested 1932, abbreviation of pictures, first used in Variety magazine, along with other similar words that the magazine calls slanguage http://www.variety.com/index.asp?layout=slanguage.