In many cultures, including Western cultures, it is customary to show respect to someone older than you when greeting them. Here are some common ways to greet someone older in a formal or respectful manner:
"Hello" or "Hi" followed by their title and last name: For example, "Hello, Mr. Smith" or "Hi, Mrs. Johnson."
"Good morning/afternoon/evening" followed by their title and last name: Such as "Good morning, Professor Brown" or "Good afternoon, Dr. Patel."
"Sir" or "Ma'am/Madam": Using these honorifics is a sign of politeness and respect. For instance, "Good evening, Sir" or "Hello, Ma'am."
Bowing or nodding: In some cultures, a bow or nod of the head is a respectful greeting for someone older or of higher social status.
Handshake: In many Western cultures, a firm handshake is a common greeting for both older and younger individuals in professional settings.
Use of honorifics: In more formal settings or in some cultures, you might use specific honorific titles like "Mr.," "Mrs.," "Dr.," "Professor," etc., followed by their last name when addressing someone older.
Remember that customs may vary depending on the specific country or region within a country. If you're unsure about the appropriate way to greet someone older in a particular culture, observing how others interact and following their lead can be helpful.