What is the X in X-mas?
1620s, from Medieval Latin heterogeneus, from Greek heterogenes, from heteros "different" (see hetero-) + genos "kind, gender, race stock" (see genus). Earlier in same sense was heterogeneal (c.1600).
heterogeneous het·er·o·ge·ne·ous (hět'ər-ə-jē'nē-əs, -jēn'yəs)adj. Composed of parts having dissimilar characteristics or properties.
Composed of unrelated parts, different in kind. Often used in the context of distributed systems that may be running different operating systems or network protocols (a heterogeneous network). For examples see: interoperable database, middleware. Constrast homogeneous. (1999-05-06)