What is your definition of a half brother/sister

United States
@kitty42 (3907)
September 7, 2009 9:29pm CST
Lets say a mother has 2 children with two different fathers are these two siblings only half related? this is a question that I have thought about, you come from the same woman and yet you are half my sibling how does this work? really I understand dad did his part but do we consider mom more than half considering the fact she has to do most of the work I hear people say this is my half sister or half brother I don't really understand it, can you help me out? How do we define a half brother/sister?