What is the X in X-mas?
late 15c., a back-formation from maceration or else from Latin maceratus, past participle of macerare "soften, make soft, soak, steep," related to maceria "garden wall," originally "of kneaded clay," from PIE *mak-ero-, suffixed form of root *mag- "to knead" (cf. Greek magis "kneaded mass, cake," mageus "one who kneads, baker;" Old Church Slavonic mazo "to anoint, smear;" Breton meza "to knead;" Middle Irish maistir "to churn"), also "to fashion, fit" (cf. make (v.)). Related: Macerated; macerating.
macerate mac·er·ate (mās'ə-rāt')
v. mac·er·at·ed, mac·er·at·ing, mac·er·ates
To make soft by soaking or steeping in a liquid.
To separate into constituents by soaking.