- American Proprietary Eponyms Database updated December 8, 1997 An eponym is a general term used to describe from what or whom something derived its name. Therefore, a proprietary eponym could be considered a brand name (product or service mark) which has fallen into general use. We've all seen it happen. The trademarks of today become the household word of tomorrow. Well, some say tis the price ...www.searstower.org/rkrause/brands.html