What is a courteous closing in a letter referred to as?

A courteous closing in a letter is referred to as a "complimentary close." This term specifically identifies the signature line that follows the body of a letter and precedes the sender's name. It reflects the polite tone of the correspondence, allowing the writer to express goodwill and professionalism. Common examples include phrases like "Sincerely," "Best regards," or "Yours truly," which maintain the formal nature of the communication.

The term "complimentary close" is widely recognized in both personal and business letters, making it the standard term used in writing etiquette. Other options, while they may sound plausible, do not have the same established recognition in letter writing. For instance, "final note," "cordial close," and "sincere ending" do not accurately capture this element of letter composition as universally acknowledged terms.