1. "Mr." is the abbreviation for "gentleman" in English, derived from the Latin word "dominus," which is a respectful term for an adult male.2. In international and business settings, it is common courtesy to address men as "Mr." regardless of their age, position, or social status.3. Adding the surname, such as "Mr. Smith," indicates a respectful address for a male with the surname Smith.4. "Ms." is the abbreviation used to address women in a respectful manner. It does not reveal the marital status of the woman, making it suitable for formal occasions.5. "Madam" can also be used as a respectful term for married women, particularly in formal or semi-formal settings, such as in the service industry.6. When using these titles, it is important to consider the context and cultural background to avoid any potential offense.7. Overall, both "Mr." and "Ms." are common respectful terms used in international communication to address individuals.8. The use of these titles may vary in different cultures and contexts, so attention to detail and differences is necessary in practical application.