In genealogical terms, this person is your first cousin once removed. To understand how to reach this conclusion, it may be helpful to break the family link down into the following relationships:
- Your mother's mother is your grandmother.
- Your mother's mother's sister is your great aunt, sometimes called a grand aunt. This person is also your mother's aunt.
- The child of your great aunt is a cousin but is once removed because you do not belong to the same generation. In fact, this person belongs to the same generation as your mother, which explains why they are first cousins but are 'removed' from yourself.
A simple trick to work out the connection between cousins is to look at the grandparents. Those who share a grandparent, for example, are first cousins, while those who share a great-grandparent are second cousins.
Next, take a look at the age gap between your cousins: if there is one generation between you and your cousin, for instance, you are once removed. If there are two generations separating you then you are twice removed.