1. nephew
Your siblings children are nephews (boys) or nieces (girls).
2. mother
If your brother is your full-blood brother, you would both have the same mother. If you had different fathers, you'd still have the same mother, but he would be your half-brother since you are only related by half your blood.
3. father OR your uncle
This is tricky because you have two grandfathers - one on your mother's side and one on your father's side. If it's your grandfather on your father's side, his son is your father. If it's the grandfather on your mother's side, his son is your uncle.
4. Step-Mom
The word goes before any immediate family member that has joined the immediate family due to a parent's marriage. This includes step-sister, step-brother, step-father.
5. cousins
Cousins are the children of your parents' siblings. You share the grandparents from that side of the family. For example, your cousins on your mother's side of the family call your mom's parents grandparents, just like you would.
