What is the X in X-mas?
late 14c., "a maker, a smith," agent noun from forge (v.). Meaning "a counterfeiter" is from 1550s.
late 14c., "a smithy," from Old French forge (12c.) "forge, smithy," earlier faverge, from Latin fabrica "workshop," from faber (genitive fabri) "workman in hard materials, smith" (see fabric). As the heating apparatus itself, from late 15c.
c.1300, "to make, shape, create," from Old French forgier, from Latin fabricari "to frame, construct, build," from fabrica "workshop" (see forge (n.)). Meaning "to counterfeit" is early 14c. Related: Forged; forging.