What's "pièce de résistance" mean and when's it used?

Native speaker’s answer
Rebecca
"Pièce de résistance" is most commonly used to refer to a masterpiece artwork and is similar in meaning to "magnum opus." However, in other contexts it can also mean the most important or remarkable feature of something. Ex: The pièce de résistance of this meal was the delicious dessert. Ex: This painting is the pièce de résistance of the entire collection.