An extended family member is someone who is related to you, but not by blood. A stepson is a son of one's spouse from a previous marriage. A niece is the daughter of one's sibling. An inlaw is the relative of one's spouse. A soninlaw is the husband of one's daughter. A halfsister is someone who shares only one parent with you. A motherinlaw is the mother of one's spouse. A distantcousin is a cousin who is more distantly related than a first cousin.