Family

It took me 19 years to find this out.

Parent: either of your two-person development team;
Siblings: your parents' other children;
Grandparents: your Mum and Dad's parents;
Great Grandparents: your Grandparents' parents;
Great Great Grandparents: your Great Grandparents' parents;
Aunt or Uncle: a child of your Grandparents that wasn't your Parent;
Grand Aunt or Uncle: a child of your Great Grandparents that wasn't your Grandparent;
Great Grand Aunt or Uncle: a child of your Great Great Grandparents that wasn't your Great Grandparent;
Cousin: a child of your Aunt or Uncle (that is, a Grandchild of your Grandparents that isn't you or any of your siblings);
Second Cousin: a child of a child of your Grand Aunt/Uncle (that is, any Great Grandchild of your Great Grandparents that isn't you, your siblings or your cousins);
Third Cousin: a child of a child of a child of your Great Grand Aunt/Uncle (that is, any Great Great Grandchild of your Great Great Grandparents that isn't you, your siblings, your Cousins, or your Second Cousins);
First Cousin Once Removed: either a child of your Cousin (that is, any Great Grandchild of your Grandparents that isn't your child) or a child of your Grand Aunt/Uncle (that is, any Grandchild of your Great Grandparents that isn't your parent, your Aunt or your Uncle; i.e. your Aunt/Uncle's Cousin);
First Cousin Twice Removed: either a Grandchild of your Cousin (that is, any Great Great Grandchild of your Grandparents that isn't your Grandchild) or a child of your Great Grand Aunt/Uncle (that is, any Grandchild of your Great Great Grandparents that isn't your Grandparent, Grand Aunt/Uncle; i.e. your Grandparent's Second Cousin);
Second Cousin Once Removed: either a Great Grandchild of your Grand Aunt/Uncle (that is, any Great Great Grandchild of your Great Grandparents that isn't your child) or a Grandchild of your Great Grand Aunt/Uncle (that is, any Great Grandchild of your Great Great Grandparents that isn't your parent, your Aunt, your Uncle or your First Cousin Once Removed; i.e. your Aunt or Uncle's Second Cousin);
Second Cousin Twice Removed: either a Great Great Grandchild of your Grand Aunt/Uncle (that is, any Great Great Great Grandchild of your Great Grandparents that isn't your Grandchild or your First Cousin Twice Removed) or your Grandparent's Third Cousin.

From hereon in (Third Cousin Once/Twice Removed etc.), they either don't exist yet or you have absolutely zero chance of ever meeting them. Suffice to say that I have it on very good authority that Australian Labor Party Minister for Agriculture Kim Chance MP is my First Cousin Twice Removed. (Think an Australian Hilary Benn.)

So there you go. Bookmark this whilst you remember.