condiment
Something added to food to give it extra flavor.
A condiment is something you add to food to give it extra flavor. Ketchup, mustard, mayonnaise, hot sauce, and soy sauce are all condiments. People sprinkle, spread, or pour condiments onto their food to make it taste exactly the way they like it.
Before refrigerators existed, people used salt, vinegar, and spices (early condiments) to keep food from spoiling. Over time, these flavor-boosters became popular for making meals more interesting and delicious, beyond their original preserving purpose.
Different cultures have their own favorite condiments. In Japan, people might reach for wasabi or pickled ginger. In India, chutneys made from mangoes, coconut, or mint appear at most meals. In America, the classic trio is ketchup, mustard, and mayonnaise. Mexican cuisine features salsa and hot sauces, while Chinese cooking uses soy sauce and chili oil.
Notice that condiments are optional additions, not main ingredients. A hamburger is still a hamburger whether you add ketchup or not, but the condiment lets you customize it to your taste. When someone asks “would you like any condiments with that?” they're giving you the chance to personalize your meal.