Also spelt façade.
1. An artificial or misleading front. A misrepresentation. Examples: Bob's calm demeanour was only a façade. He was really a psychopathic cannibal who believed himself blessed by the gods of Mars and charged with secretly eating world leaders; or The make-up she wore created a façade of beauty that hid the scars she still had from childhood.
2. The front or face of a structure. Typically this refers to the most important or noteable face of a building. For example, the side of a building with the primary entrance. This definition is related to the Webster 1913's fassade write-up. Example: The western façade of the library had been completely covered in dirt.
Note: I've been unable to find fassade in any modern dictionary I've checked. A Google search resulted in numerous German results. Running fassade through the translator at systransoft.com for German-to-English translations, it appears to be German for front. Albert Herring tells me "fassade" is the original French spelling, which became "façade" in 1611.
Etymology: From the French façade, orignally fassade (same meaning), from the Italian facciata (same meaning), from faccia (meaning "face").
Source for etymology: Merriam Webster's dictionary (m-w.com), dictionary.com, and Albert Herring (who found the date from Robert Historique).