madam
A very polite way to address a woman respectfully.
Madam is a polite, formal way to address a woman, especially when you don't know her name or when you want to show respect. If a waiter approaches a table, he might say “Good evening, madam” to a female customer. A student might say “Yes, madam” when answering a teacher they don't know well. Shop employees often use it with customers: “May I help you find something, madam?”
It's the female equivalent of “sir.” While “madam” sounds quite formal today, it's still common in service jobs, official settings, and some schools.
You might also see “madam” used as a title before a woman's job title in very formal situations, like “Madam President” or “Madam Ambassador.”
The word can be shortened to “ma'am” (rhymes with “ham”), which sounds less formal but still respectful. In some regions, especially in the American South, children are taught to say “yes, ma'am” and “no, ma'am” to adult women as a sign of good manners. In other places, some people prefer different forms of address, so it's thoughtful to pay attention to what someone asks to be called.