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.
Your mother’s mother’s sister is your mother’s aunt and your great aunt. That woman’s daughter is your mother’s first cousin. Since you are your mother’s child, you and her first cousin are first cousins once removed. You might feel like she is more of your aunt as you are of different generations, but the technical term is that you are first cousins once removed.
While it does seem wrong to call this person your cousin, the phrase “once removed” changes things. People who are anything “once removed” from one another are in a different generation. People who are “twice removed” are two generations apart. Since you and your mother’s cousin are one generation apart, you are first cousins once removed.
Since you mentioned second cousins, if the woman you are asking about (your first cousin once removed) has children, they would be your second cousins. Please follow the link below for further information.