On talk/reality/music competition shows, I hear 20-somethings from the South (USA) refer to the host/judge/etc., when it's a female, as "ma'am". My question is whether there's an unwritten age dividing line when you, as a younger person, stop calling a lady a "ma'am"? In other words, if you think they are 20 years older than you, is it okay to call the woman a "ma'am"? What if only 10 years older? Maybe I should ask the other way---do same-aged women, as an example, call each other "ma'am", in other words, when there's no age difference? Sorry, this sounds confusing. I'm having trouble formulating the question.