Dijon mustard is a smooth, pale condiment made from brown or black mustard seeds blended with white wine or verjuice instead of vinegar, giving it a sharper, less acidic bite than yellow mustard. It takes its name from Dijon, in France's Burgundy region, long a center of French mustard-making, with records of mustard production there going back to the medieval period.
It's a key ingredient in French sauces, dressings, and marinades, and pairs well with thyme, rosemary, black pepper, honey, and vinegar-based dressings.
Note that "Dijon mustard" is a style, not a protected regional product: most Dijon mustard sold today, including brands still labeled Dijon, is made outside the Dijon region.