The term MAYONNAISE INGREDIENT can be broken down into three crossword solutions: EGG (3 letters), FENNEL (6 letters), and LEMONJUICE (10 letters). Eggs are a common ingredient in mayonnaise, providing the emulsifying properties that help bind the other ingredients together. FENNEL is an aromatic herb with a mild licorice flavor, which can add a unique flavor to mayonnaise. Lemon juice is also a popular addition to mayonnaise, adding a tartness to the condiment. All three of these ingredients are commonly used in the making of mayonnaise.