Final answer:
P.S. stands for Post Scriptum, which is a Latin phrase meaning 'after writing.' It is used at the end of a letter to add extra information or thoughts that were not included in the main body of the text.
Step-by-step explanation:
P.S. stands for Post Scriptum. It is a Latin phrase that translates to 'after writing' or 'after the main body of the text.' When you use P.S. at the end of a letter, it is used to add additional information or thoughts that were not included in the main content of the letter. It is commonly used to emphasize a point or provide clarification. For example, 'P.S. Don't forget to bring your textbook tomorrow!'