"Lei è una cameriera."
Traduzione:She is a waitress.
If you can understand what I'm writing, here is the difference:
A "waitress" is a female food or beverage server. She does not cook the food, she only brings it to you.
A "waiter" is a male food or beverage server.
A "maid" is someone who cleans your room or your house. They do not bring you food.
A "servant" is someone who does anything for you, personally. You pay them and they are able to go to their own home after work, unless you've asked them to live with you. They might bring you food, if you asked them to. Some rich people still have servants.
A "slave" is someone who does whatever you want them to do, but they either have no other place to be, or you do not pay them very well. Slaves are illegal, because they belong to you (you "own" them"). No one has a slave any more; that was a past age.