They share a common grandparent. That makes them first cousins.
They are first cousins.
They are first cousins once removed.
He is your nephew, and you are his uncle.
If your niece's is by your sister but the brother is by your sisters new husband & another woman there would be no blood relation. If not then he's the nephew
I cannot see why not. There is no blood relationship between you and your sisters ex-husband.
If your sister-in-law is married to your brother or sister, her nephew may be your nephew.Otherwise her nephew is not blood related to you, But he is related by marriage to you and he is stort of newphew in law.
Blood relationship.
If you are a female you could be talking about yourself. You could also refer to a sister this way. This could also refer to a cousin of yours, since your aunt's husband may have nieces through more than one sibling (either his siblings or your aunt's siblings). It is not clear whether you are related to your aunt or to your uncle by blood, but it is very probably one of them and not both.If your aunt is the sister of one of your parents, then her husband (your uncle) may have nieces who are not related to you at all. These would be the daughters of his siblings.
These people are part of your extended family. They are not related by blood to you and there is no simple word for the relationship. They are your husband's sister-in-law and brother-in-law, of course.
If you Wife blood realated to him then you are his uncle by marriage and even thought you not blood related.Uncle or Aunt by marriage are one realtion thats 100% realted by marriage.Aunt or Uncle in law is how you sibings are realted to him but they are only 50% realated to him by marriage.
Yes, your niece is the daughter of your sibling (sister or brother), so there is continuity of "blood" (i.e., genetic descent) from your common parent(s), assuming your sister/brother and her/his daughter are not adopted.
If your brother-in-law is your wife's brother, his son is your nephew and you are his uncle or aunt. If your brother-in-law is sister's husband and his son is also her son, he is your nephew and you are his uncle or aunt. If the brother-in-law's son is from a marriage to a woman other than your sister, and your sister has not adopted him, he is not related to you. However, you may choose to treat him as your nephew, especially if he came into your life as a young child and considers your sister to be his mother.
It depends on the actual relationship. It is possible for your aunt's husband's brother to be your father. (She would be an aunt by marriage.) If your aunt is the actual sibling of one of your parents, then, yes, because he is not related to you "by blood ."