A maid is a female domestic worker who typically performs cleaning and household tasks in someone else's home. The clue "One knocking on many doors" suggests that a maid goes from house to house, often providing cleaning services for multiple households.
Note: The provided meaning of the answer is for the latest New York Times crossword puzzle clue: One of eight "a-milking" in a Christmas carol. Explanations are generated by AI and may be inaccurate.