What is the X in X-mas?
(plural corpora), late 14c., from Latin corpus, literally "body" (see corporeal). The sense of "body of a person" (mid-15c. in English) and "collection of facts or things" (1727 in English) both were present in Latin. Corpus Christi (late 14c.), feast of the Blessed Sacrament, is the Thursday after Trinity Sunday. Also used in various medical phrases, e.g. corpus callosum (1706, literally "tough body"), corpus luteum (1788, literally "yellow body").
corpus cor·pus (kôr'pəs)
n. pl. cor·po·ra (-pər-ə)
The human body, consisting of the head, neck, trunk, and limbs.
The main part of a bodily structure or organ.
A distinct bodily mass or organ having a specific function.