I just noticed your name and it occurred to me that you may well be trying to find out if Big is a German word. Since family names go back many hundreds of years, the meaning may have changed over time. There is no German word *big* that I'm aware of though. Another possibility is that your ancestors may have changed their name from Großhaus to Bighaus when they emigrated to the U.S. Many Europeans did that with their names hoping to fit in more quickly. Hope this helps.