The phrase "mon chéri" means "my darling" in French. The phrase is commonly used in the French language as a term of endearment.
In French, the word "mon" is the masculine form of the English word "my." This means that "mon chéri" would be said to a man, as opposed to "ma chérie" which would be said to a woman. The "n" in the word "mon" is intended to be be pronounced nasally. "Mon chéri" often follows the words, "Je t'aime," which is French for "I love you." The phrase can also be shortened to simply "mon cher," which means "my dear." The phrase has become very popular in movies, novels and even as a business name, especially for wedding companies.