When referring to the husband of one's aunt the term uncle is usually used. A great-uncle/granduncle/grand-uncle is the brother of one's grandparent.

How do you refer to a great great-uncle?

Great-Great Uncle: I-1. A brother of one of your 8 great grandparents. Note the slightly confusing terminology – the siblings of your great grandparents have two “greats” in their relationship title, compared to only one “great” in their sibling, your great grandparent. Great-Great Aunt: I-10.

What is a great-uncle or great aunt?

What is the definition of a great-uncle or a great-aunt? The definition of a great-aunt or great-uncle is someone who is a sibling of one of our grandparents. The most recent common ancestor (MRCA) that we share with our great-aunts and uncles is our great-grandparents.