Sentence:  I grew up thinking that the blue and white Miracle Whip salad dressing jar in the fridge held the same substance the rest of the world knew as <WSD>mayonnaise</WSD>. / Now I know that <WSD>mayonnaise</WSD> is something entirely different. 
Meaning of the word marked with <WSD> tags:  A dressing made from vegetable oil, raw egg yolks and seasoning, used on salads, with french fries, in sandwiches etc.