"Mam" and "Ma'am" are both honorific terms used to address or refer to a woman in a respectful manner. The main difference between the two lies in their regional variations and formality:
"Mam": "Mam" is a more informal and colloquial term used in some dialects and regional accents, especially in parts of the southern United States and certain English-speaking countries. It is a shortening of "madam" and is pronounced like "mam" with a short "a" sound.
"Ma'am": "Ma'am" is the standard and more formal way of addressing a woman politely. It is the contraction of "madam" and is pronounced with a long "a" sound, like "mahm." "Ma'am" is widely used in both written and spoken English, and it is considered appropriate in most formal and professional settings.
In summary, "Mam" is a less formal and more regional variant of the term, while "Ma'am" is the accepted standard and is used more widely across different English-speaking contexts. It's essential to use the appropriate term based on the level of formality required in a particular situation and to be attentive to regional preferences when addressing others.