A spinster is a woman who is not married or in any kind of relationship.
The term is usually used to describe an older unmarried woman, while bachelor can be used to describe a man of any age.
A waiter is a female person who waits on tables in a restaurant, taking orders, serving customer's food and drinks and clearing tables when they are finished.
A woman, sometimes called a lady, is an adult female person. Your mother and your grandmother are women.