From the Arcade Dictionary of Word Origins:
- [OE] A distant relative of bridge, Old Slavic bruvino, "beam', coupled with the name of the cognate Old Norse bryggja "gangway" suggest that the underlying etymological meaning of the word is not "spanning structure" but "road or structure made of logs". The Norse word, incidentally, produced the scottish nand northern English brig "bridge".
The card game bridge is first unambiguously mentioned in the in English in the 1880s, and its name has no connection with the "spanning" bridge. The earliest known recorded form of the word is biritch. Its source has never been satisfactorily explained, but since a game resembling bridge is known to have been played for many centuries in the Middle East, it could well be that the name originated in that area. One suggestion put forward is that it came from an recorded Turkish bir-u, literally "one-three" (one hand being exposed during the game while the other three are concealed).