Immediate Family
Your father's wife is ...
Your mother
Your mother's sister is ...
your aunt
Your mother's son is ...
Your brother
Your father's brother's son is ...
your cousin
Your sibling's child is ...
your niece / nephew
Your cousin's father is ...
your uncle
Your father's father is ...
your grandfather
Your spouse's sister's husband is ...
brother-in-law
Your spouse's mother is ...
your mother-in-law
Your mother's husband (not your biological father) is ...
stepfather