A chupah is the canopy made of cloth and poles under which a Jewish couple gets married. It has also become synonymous with the wedding ceremony itself, (as in "Chupah 4pm... Carriages 11pm," both being ancient words with a venerable place on Anglo-Jewish wedding invitations, though chupahs seem to have long outlived carriages in their practical usefulness.)
The word chupah appears in the Bible. The sunrise is compared to "a bridegroom coming out of his chupah" (Psalms 19:6). There is, however, a disagreement about the etymology of the word. Some authorities claim that it is derived from the word "chafah," meaning "to cover" or "hide" (as in Esther 6:12), where Haman emerges from the king's banquet "chafui rosh," with his head covered. Others maintain that the root is "chafaf," which means "to cover" in the sense of "to protect," (as in Devarim 33:12, where the tribe of Benjamin is blessed that it will dwell permanently under God's protection.)
The chupah symbolically represents the couple's first home. By standing under a chupah they publicly enact their living together. There are two parts to the wedding ceremony; the first, kiddushin, "betrothal," is completed through the man giving a ring to the woman. The second, "nesuin," "marriage," is accomplished by the couple standing under the chupah (or, according to some authorities by their being alone together for a few minutes after the ceremony).