In Enid Blyton's "Famous Five" series, the aunt and uncle of the main characters are Aunt Fanny and Uncle Quentin. They are the guardians of Julian, Dick, Anne, George (Georgina), and Timmy the dog, and often provide a home base for their adventures.
Uncle
'Great aunt' and 'Great uncle' are what your children properly call your own aunt and uncle. Your aunt and uncle are the brother and sister of your parent. Your parent is your children's grandparent.
Aunt is 'tante' and uncle is 'oncle' in French. As a pet name, Auntie is 'Tatie'.
Harry's aunt is Aunt Pentunia and his uncle is Uncle Vernon. He also has a cousin, Dudley. They look after him when hes not at Hogwarts. His aunt is his mother's sister. She is not a wizard.
Great aunt or uncle.
Your uncle. Assuming your aunt is a sibling of one of your parents, your uncle would be defined as whoever happens to be married to her. You're welcome to continue calling the first husband your uncle if you feel it's appropriate.
In English, you call your maternal uncle's wife "aunt." It's not rocket science, honey. Just like how you call your paternal uncle's wife "aunt," keep it simple and call her the same thing.
The sister of your uncle is typically referred to as your aunt. If she is the sister of your uncle by marriage, she is still considered your aunt by that relationship. If she is your uncle's biological sister, she is also your aunt. In some cultures, the term "aunt" can be used more broadly to refer to close family friends as well.
Your nephew's daughter is your great niece. You are her great aunt (if you are a woman) or her great uncle (if you are a man).
Uncle Sam
Your aunt's child, son or daughter, is your First Cousin. The same is true for your uncle's children.
Aunt Alexandra's husband's name is never explicitly mentioned in the novel "To Kill a Mockingbird." He is known simply as "Uncle Jimmy."