Half - siblings are people who share one parent but not both. They may share the same mother but different fathers (in which case they are known as uterine siblings or maternal half - brothers / half - sisters), or they may have the same father but different mothers (in which case, they are known as agnate siblings or paternal half - brothers / half - sisters. In law, the term consanguine is used in place of agnate). They share only one parent instead of two as full siblings do and are on average 25 % related.
what is the meaning of half brother or sister
share one parent but not both