What is the X in X-mas?
late 14c. (late 12c. in surnames), from Old French pance (Old North French panche) "belly, stomach," from Latin panticem (nominative pantex) "belly, bowels" (cf. Spanish panza, Italian pancia); possibly related to panus "swelling" (see panic (n.2)).
paunch (pônch, pänch)
The belly, especially a protruding one; a potbelly.